System and method to facilitate small cell uplink power control in a network environment

ABSTRACT

A method is provided in one example embodiment and may include calculating, by one or more of a plurality of small cell radios, one or more sets of candidate power control parameters using a first interference constraint for uplink user equipment (UE) transmissions for UE served by the one or more of the plurality of small cell radios; determining, at a central management entity, whether an average of a sum of an expected interference for UE associated with the plurality of small cell radios violates a second interference constraint for any of the one or more sets of candidate power control parameters; and generating one or more messages for each of the plurality of small cell radios identifying one or more particular sets of power control parameters that provide for meeting the second interference constraint.

TECHNICAL FIELD

This disclosure relates in general to the field of communications and,more particularly, to a system and method to facilitate small celluplink power control in a network environment.

BACKGROUND

Networking architectures have grown increasingly complex incommunications environments, particularly mobile wireless environments.Mobile communication networks have grown substantially in subscriberbase as end users become increasingly connected to mobile wirelessenvironments. As the number of mobile subscribers increases, efficientmanagement of communication resources becomes more critical. Uplinktransmissions are typically scheduled for user equipment (UE) served bya particular cell radio. Generally, power control for the uplinktransmissions varies depending on path loss between UE and a servingcell radio. In some cases, uplink transmissions cause interference toother neighboring cell radios. In the case of small cell networks,uplink transmissions towards a serving small cell radio can causeinterference to neighboring small cell radios as well as neighboringmacro cell radios. As the number of user equipment (e.g., the number ofsubscribers) increases, the possibility of uplink interference betweenneighboring cell radios also increases, which can lead to inefficientnetwork and UE performance. Accordingly, there are significantchallenges in providing small cell uplink power control in a networkenvironment.

BRIEF DESCRIPTION OF THE DRAWINGS

To provide a more complete understanding of the present disclosure andfeatures and advantages thereof, reference is made to the followingdescription, taken in conjunction with the accompanying figures, whereinlike reference numerals represent like parts, in which:

FIG. 1A is a simplified block diagram illustrating a communicationsystem to facilitate small cell uplink power control in a networkenvironment according to one embodiment of the present disclosure;

FIG. 1B is a simplified schematic diagram illustrating example detailsassociated with an example resource block that can be associated withuplink transmissions in accordance with one potential embodiment of thecommunication system;

FIGS. 2A-2C are simplified block diagrams illustrating additionaldetails associated with various potential embodiments of thecommunication system;

FIG. 3 is a simplified flow diagram illustrating example operationsassociated with providing small cell uplink power control in a networkenvironment in accordance with one potential embodiment of thecommunication system;

FIG. 4 is a simplified flow diagram illustrating other exampleoperations associated with providing small cell uplink power control ina network environment in accordance with one potential embodiment of thecommunication system;

FIG. 5 is a simplified flow diagram illustrating yet other exampleoperations associated with providing small cell uplink power control ina network environment in accordance with one potential embodiment of thecommunication system;

FIG. 6 is a simplified flow diagram illustrating yet other exampleoperations associated with providing small cell uplink power control ina network environment in accordance with one potential embodiment of thecommunication system; and

FIG. 7 is a simplified flow diagram illustrating yet other exampleoperations associated with providing small cell uplink power control ina network environment in accordance with one potential embodiment of thecommunication system.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS Overview

A method is provided in one example embodiment and may includecalculating, by one or more of a plurality of small cell radios, one ormore sets of candidate power control parameters using a firstinterference constraint for uplink user equipment (UE) transmissions forUE served by the one or more of the plurality of small cell radios;receiving, at a central management entity, the one or more sets ofcandidate power control parameters from each of the one or more of theplurality of small cell radios; determining, at the central managemententity, whether an average of a sum of an expected interference for UEassociated with the plurality of small cell radios violates a secondinterference constraint for any of the one or more sets of candidatepower control parameters; and generating one or more messages for eachof the plurality of small cell radios identifying one or more particularsets of power control parameters that provide for meeting the secondinterference constraint. In some instances the central management entitymay be a Self-Organizing Network (SON) management system incommunication with each of the plurality of small cell radios.

In some instances, each set of power control parameters can include afirst power control parameter associated with a power offset for UEtransmissions toward a particular small cell radio; and a second powercontrol parameter associated with an amount of path loss between UE andthe particular small cell radio that is inverted for UE transmissionstoward the particular small cell radio. In some instances, the firstinterference constraint may be associated, at least in part, withinterference generated towards each of the one or more of the pluralityof small cell radios by one or more UE associated with at least onemacro cell radio. In some instances, the second interference constraintmay be associated, at least in part, with interference generated by theUE associated with the plurality of small cell radios towards at leastone macro cell radio.

In some cases, for a particular small cell radio, calculating aparticular set of candidate power control parameters can further includesetting a first expected Signal to Interference plus Noise Ratio (SINR)threshold value associated with cell edge UE served by the particularsmall cell radio for the first interference constraint; setting a secondexpected SINR threshold value associated with cell interior UE served bythe particular small cell radio for the first interference constraint;calculating the particular set of candidate power control parameters forthe particular small cell radio using the first expected SINR thresholdvalue and the second expected SINR threshold value for the firstinterference constraint; and generating a message toward the centralmanagement entity including the set of power control parameters. In someinstances, for the particular small cell radio, the method can includereducing at least one of the second expected SINR threshold valueassociated with cell interior UE or the first expected SINR thresholdvalue associated with cell edge UE if the central management entitydetermines that the second interference constraint is violated; andrepeating the calculating and the generating for the particular smallcell radio until the central management entity determines that thesecond interference constraint is satisfied.

In other cases, for a particular small cell radio, calculating sets ofcandidate power control parameters can further include setting a firstrange of first expected Signal to Interference plus Noise Ratio (SINR)threshold values associated with cell edge UE served by the particularsmall cell radio for the first interference constraint; setting a secondrange of second expected SINR threshold values associated with cellinterior UE served by the particular small cell radio for the firstinterference constraint; calculating sets of candidate power controlparameters for the particular small cell radio using each of the firstexpected SINR threshold value of the first range and each of the secondexpected SINR threshold value of the second range for the firstinterference constraint; and generating one or more messages toward thecentral management entity including the sets of power controlparameters.

Another method is provided in another example embodiment and may includedetermining UE path loss information associated with one or more UEserved by one or more small cell radios; determining macro path lossinformation associated with each of the one or more small cell radiosand a macro cell radio; determining, at a central management entity, oneor more sets of optimized power control parameters for uplink UEtransmissions for the one or more UE served by the one or more smallcell radios, wherein the one or more sets of optimized power controlparameters satisfy a first interference constraint associated withlimiting interference between the one or more small cell radios andsatisfy a second interference constraint associated with limitinginterference toward the macro cell radio; and generating one or moremessages for each of the one or more small cell radios identifying theone or more sets of optimized power control parameters.

In some instances, each set of optimized power control parameters caninclude a first power control parameter associated with a power offsetfor UE transmissions toward a particular small cell radio; and a secondpower control parameter associated with an amount of UE path lossbetween UE served by the particular small cell radio that is invertedfor UE transmissions toward the particular small cell radio. In someinstances, the UE path loss information can include, at least in part, amaximum estimated UE path loss for one or more cell edge UE served by aparticular small cell radio; and a maximum estimated UE path loss forone or more cell interior UE served by the particular small cell radio.

In some instances, the macro path loss information can be based, atleast in part, on signal strength information for the macro cell radioas measured by one or more UE served by a particular small cell radio.In some instances, the UE path loss information and the macro path lossinformation can be determined by a particular small cell radio that isexperiencing the highest interference from one or more macro UE servedby the macro cell radio.

In some cases, determining the one or more sets of optimized powercontrol parameters can further include: calculating, at the centralmanagement entity, one or more sets of candidate power controlparameters that meet the first interference constraint for one or moreSignal to Interference plus Noise Ratio (SINR) threshold valuesassociated with cell edge UE served and one or more SINR thresholdvalues associated with cell interior UE served by a particular smallcell radio; determining whether an average of a sum of an expectedinterference for the one or more UE served by the one or more small cellradios satisfies the second interference constraint for any of the oneor more sets of candidate power control parameters; and identifying theone or more sets of optimized power control parameters as those one ormore corresponding sets of power control parameters that satisfy thesecond interference constraint.

EXAMPLE EMBODIMENTS

Referring to FIG. 1A, FIG. 1A is a simplified block diagram illustratinga communication system 100 to facilitate small cell uplink (UL) powercontrol in a network environment according to one embodiment of thepresent disclosure. This particular configuration may be tied to the 3rdGeneration Partnership Project (3GPP) Evolved Packet System (EPS)architecture, also sometimes referred to as the Long Term Evolution(LTE) EPS architecture. Alternatively, the depicted architecture may beapplicable to other environments equally.

The example architecture of FIG. 1A can include users operating userequipment (UE) 112 a-112 d, one or more small cell radio(s) 114 a-114 b,a macro cell radio 116 a radio access network (RAN) 120, a centralmanagement system 122 and a service provider network 130. Centralmanagement system 122 can include a central power management module 150.Each small cell radio 114 a-114 b can be logically connected to centralmanagement system 122 and service provider network 130. FIG. 1B is aschematic diagram illustrating various example details that can beassociated with communication system 100 and will be discussed inconjunction with FIG. 1A.

Each small cell radio 114 a-114 b can be associated with a correspondingsmall cell radio coverage area, as indicated by the respectivedashed-line circle surrounding each respective small cell radio 114a-114 b. Macro cell radio 116 can be associated with a correspondingmacro cell radio coverage area, as indicated by the dashed-line hexagon.In various embodiments, the macro cell radio coverage area for a givenmacro cell radio (e.g., macro cell radio 116) can overlap, in whole orin part, small cell radio coverage areas for one or more small cellradios (e.g., respective coverage areas for respective small cell radios114 a-114 b). It should be understood that the coverage areas shown inFIG. 1A are provided for illustrative purposes only, and are not meantto limit the broad scope of the teachings of the present disclosure. Anyother coverage areas (e.g., coverage area size/range) can be provided bycell radios within the scope of the present disclosure.

In various embodiments, UE 112 a-112 d can be associated with users,employees, clients, customers, etc. wishing to initiate a flow incommunication system 100 via some network. The terms ‘user equipment’,‘mobile node’, ‘end user’, ‘user’, and ‘subscriber’ are inclusive ofdevices used to initiate a communication, such as a computer, a personaldigital assistant (PDA), a laptop or electronic notebook, a cellulartelephone, an i-Phone™, i-Pad™, a Google Droid™ phone, an IP phone, orany other device, component, element, or object capable of initiatingvoice, audio, video, media, or data exchanges within communicationsystem 100. UE 112 a-112 d may also be inclusive of a suitable interfaceto a human user such as a microphone, a display, a keyboard, or otherterminal equipment.

UE 112 a-112 d may also be any device that seeks to initiate acommunication on behalf of another entity or element such as a program,a database, or any other component, device, element, or object capableof initiating an exchange within communication system 100. Data, as usedherein in this document, refers to any type of numeric, voice, video,media, or script data, or any type of source or object code, or anyother suitable information in any appropriate format that may becommunicated from one point to another. In some embodiments, UE 112a-112 d may have a bundled subscription for network access andapplication services (e.g., voice), etc. Once the access session isestablished, the user can register for application services as well,without additional authentication requirements. UE IP addresses can beassigned using dynamic host configuration protocol (DHCP), StatelessAddress Auto-configuration, default bearer activation, etc., or anysuitable variation thereof. In various embodiments, each UE 112 a-112 dcan include one or transmitters and/or receivers (e.g., transceivers)and one or more antenna(s) to facilitate over the air communicationswith one or more small cell radios 114 a-114 b and/or macro cell radio116.

In various embodiments, interfaces and/or a series of interfaces can beprovided in communication system 100 (e.g., for elements ofcommunication system 100), which can offer interoperation for mobility,policy control, uplink power control, interference mitigation or otheroperations between various elements of communication system 100. Forexample, interfaces can be used to exchange point of attachment,location, and/or access data for one or more end users, for example,users operating UE 112 a-112 d. In various embodiments, resourceinformation, accounting information, location information, accessnetwork information, network address translation (NAT) control, etc. canbe exchanged using a remote authentication dial in user service (RADIUS)protocol or any other suitable protocol where appropriate. Otherprotocols that can be used in communication system 100 can includeDIAMETER protocol, service gateway interface (SGi), terminal accesscontroller access-control system (TACACS), TACACS+, etc. to facilitatecommunications. In various embodiments, small cell radios 114 a-114 bmay logically be connected to each other via an X2 interface (not shownin FIG. 1), as defined in 3GPP standards.

RAN 120 is a communications interface between UE (e.g., 112 a-112 d) andservice provider network 130 via small cell radios 114 a-114 b and/ormacro cell radio 116. Via small cell radios 114 a-114 b and/or macrocell radio 116, RAN 120 may provide one or more coverage areas forservicing multiple end users and for managing their associatedconnectivity. The communications interface provided by RAN 120 may allowdata to be exchanged between an end user and any number of selectedelements within communication system 100. For example, RAN 120 mayfacilitate the delivery of a request packet (e.g., request forservice(s)) generated by a given UE (e.g., UE 112 a) and the receptionof information sought by an end user. In various embodiments, RAN 120may include 3GPP access networks such as, for example, Global System forMobile Communications (GSM) Enhanced Data Rates for GSM Evolution (EDGE)Radio Access Network (GERAN), generally referred to as 2G; UniversalMobile Telecommunications System (UMTS) Terrestrial Radio Access Network(UTRAN), generally referred to as 3G; and/or evolved UTRAN (E-UTRAN),generally referred to as 4G, Long Term Evolution (LTE) and/orLTE-Advanced (LTE-A). In various embodiments, RAN 120 may includenon-3GPP IP access networks such as digital subscriber line (DSL),Cable, wireless local area network (WLAN) (e.g., Wireless Fidelity(WiFi), Worldwide Interoperability for Microwave Access (WiMAX)) and/orthe Internet. RAN 120 is only one example of a communications interfacebetween an end user and service provider network 130. Other suitabletypes of communications interfaces may be used for any appropriatenetwork design and, further, be based on specific communicationsarchitectures in accordance with particular needs.

In general, service provider network 130 represents a series of pointsor nodes of interconnected communication paths for receiving andtransmitting packets of information that may propagate throughcommunication system 100. In various embodiments, service providernetwork 130 can be configured according to 3GPP standards to include oneor more elements of an Evolved Packet Core (EPC), a packet-switched (PS)architecture and/or a circuit-switched (CS) architecture as prescribedby 3GPP standards in order to provide services (e.g., voice, data,multimedia, etc.) and interconnectivity to UE 112 a-112 d to one or morepacket data networks (e.g., the Internet).

In various embodiments, service provider network 130 may offercommunicative interfaces between UE 112 a-112 d and selected nodes orelements in the network, and may be any local area network (LAN),wireless local area network (WLAN), metropolitan area network (MAN),wide area network (WAN), virtual private network (VPN), Intranet,extranet, or any other appropriate architecture or system thatfacilitates communications in a network environment. In variousembodiments, communication system 100 may implement a user datagramprotocol (UDP)/Internet protocol (UDP/IP) connection and use atransmission control protocol (TCP/IP) communication language protocolin particular embodiments of the present disclosure. However, any othersuitable communication protocol for transmitting and receiving datapackets within communication system 100 may be alternativelyimplemented.

In various embodiments, macro cell radio 116 can be deployed as anevolved Node B (eNodeB or eNB), which can provide cellular/mobilecoverage for a 4G/LTE macro cell network, or a Node B (NodeB), which canprovide cellular/mobile coverage for a 2G/3G macro cell network. Ingeneral a NodeB is deployed in conjunction with a Radio NetworkController (RNC), which may provide radio control for the NodeB. Invarious embodiments, macro cell radio 116 can be responsible forselecting a Mobility Management Entity (MME) or a serving General PacketRadio Service (GPRS) support node (SGSN) within service provider network130 for session establishment for each UE served by macro cell radio 116(e.g., UE 112 d), for managing radio resources for such UE, and makinghandover decisions for such UE, for example, handover to other cellradios (e.g., eNodeBs and/or HeNBs).

In various embodiments, small cell radios 114 a-114 b can be deployed ashome evolved NodeBs (HeNBs), which can provide cellular/mobile coveragefor a 4G/LTE small cell network, and/or can be deployed has Home Node Bs(HNBs), which can provide cellular/mobile coverage for a 2G/3G smallcell network. In some embodiments, small cell radios 114 a-114 b can bedeployed as ‘single-stack’ devices offering 4G/LTE or 2G/3Gconnectivity, ‘dual-stack’ devices offering 4G/LTE or 2G/3G connectivityand WiFi/WiMAX connectivity, or ‘triple-stack’ offering 4G/LTEconnectivity, 2G/3G connectivity and WiFi/WiMAX connectivity.

Typically, small cell radios operate at lower power levels as comparedto macro cell radios to provide services to proximate users, forexample, within in a business or residential environment (e.g., within abuilding, home, etc.). In some embodiments, small cell radios (e.g., 114a-114 b) can be deployed in business (e.g., enterprise) environmentswithin predefined clusters, grids or groups that can be optimized toprovide contiguous or overlapping cellular/mobile coverage forenterprise users (e.g., employees, visitors, etc.) when such users arelocated within a coverage area of small cell radios deployed in such acluster/grid. In some embodiments, small cell radios can be deployed inresidential or densely populate environments to providecellular/wireless connectivity in areas where macro cell radio coveragearea(s) may be limited and/or overloaded.

In some embodiments, small cell radios 114 a-114 b can interface withservice provider network 130 via one or more small cell gateways (notshown), which can be used to aggregate and/or manage sessions for UEconnected to the small cell network. Small cell radios can be connectedusing a standard broadband digital subscriber line (DSL), internet orcable service into service provider network 130 via the one or moresmall cell gateways. Calls can be made and received, where the signalsare sent (potentially encrypted) from a given small cell radio via thebroadband Internet protocol (IP) network to one of the serviceprovider's main switching centers. In some embodiments, small cellradios 114 a-114 b can also interface with a small cell managementsystem, which can be used to manage configurations (e.g., communicationprotocols, data models, etc.) for small cell radios 114 a-114 b. In someembodiments, the small cell management system can be included withincentral management system 122 or can be provided separate from centralmanagement system. In various embodiments, each small cell radio 114a-114 b can include one or transmitters and/or receivers (e.g.,transceivers) and one or more antenna(s) to facilitate over the aircommunications with one or more UE served thereby.

As referred to herein in this Specification, a ‘small cell radio’ (e.g.,small cell radio 114 a, 114 b) can be referred to interchangeably as a‘small cell’, a ‘femtocell’ or a ‘pico cell’. As referred to herein inthis Specification, a ‘macro cell radio’ (e.g., macro cell radio 116)can be referred to interchangeably as a ‘macro cell’, a ‘macro radio’ ora ‘macro’. As shown in FIG. 1A, UE 112 a-112 d may be served (e.g.,logically connected to via an over-the-air interface) by a serving orsource small cell or macro cell radio, as indicated by the solid linebetween each UE and a corresponding small cell or macro cell radio(e.g., UE 112 a-112 b served by small cell radio 114 a; UE 112 c servedby small cell radio 114 b; and UE 112 d served by macro cell radio 116).

As shown in FIG. 1A, central management system 122 can further includecentral power management module 150, which can, in various embodiments,aid in coordinating small cell uplink power control and/or resourcemanagement for small cell radios 114 a-114 b serving UE 112 a-112 c. Invarious embodiments, central management system 122 can be deployed asany central management entity, such as, for example, an Operations,Administration and Maintenance (OAM) entity, a Radio Management System(RMS), a Radio Resource Manager (RRM), a Self-Organizing Network (SON)management system, combinations thereof or the like. In certainembodiments, an RMS can be used in conjunction with small celldeployments, for example, to configure small cell radios 114 a-114 baccording to a particular communications protocol (e.g., technicalreport (TR) 069) and data model (e.g., TR-196 version 2).

In some embodiments, a SON management system can have visibility of,and/o may interface with one or more parallel networks such as, forexample, a macro cell network, a small cell network, a wireless localarea network (WLAN), etc. and can be used to coordinate uplink powercontrol and/or resource management for UE associated with small cellradios in a small cell deployment. In essence, a SON management system(e.g., central management system 122, depending on configuration) mayprovide a system-wide view of communication system 100 and can thereforeintelligently provision small cell uplink power control parametersand/or resources among different communication networks in thecommunication system. Accordingly, central management system 122 can beconfigured to interface with any element or node of communication system100 via one or more logical interfaces. In various embodiments, centralmanagement system 122 can be deployed within service provider network130, within cloud-based service (e.g., in a centralized SON (cSON)architecture) and/or can be deployed in a service network for aparticular deployment, such as, for example, in an enterprise small celldeployment. In some embodiments, for example, if central managementsystem 122 is configured as a SON management system, macro cell radio116 may have a logical connection to central management system 122.

Generally, Signal-to-Interference-plus-Noise Ratio (SINR) is used todescribe or quantify signal quality for downlink transmissions to UE(e.g., from a serving cell radio to a UE) and/or uplink transmissionsfrom UE (e.g., from a given UE to its serving cell radio). In someembodiments, SINR for a given UE (e.g., any of UE 112 a-112 d) can bedetermined or estimated based on one or more of: a Reference SignalReceived Quality (RSRQ) as measured by the UE for the Evolved-UniversalTerrestrial Radio Access (E-UTRA); a downlink channel quality indicator(CQI) reported by the UE, relative Reference Signal Received Power(RSRP) and/or the received signal strength for an uplink transmissiondivided by the total interference in the cell. Typically, E-UTRA isdescribed in reference to the air-interface for LTE radio access. Insome embodiments, an expected or target SINR can be used incommunication system 100 in order to determine and/or control uplinkpower control parameters for small cell UE, as discussed in furtherdetail herein.

As defined in 3GPP TS 36.214, RSRP is the linear average over the powercontributions of resource elements for resource blocks (RBs) that carrycell-specific reference signals (CRS) within a considered measurementfrequency bandwidth. RSRQ is defined as the ratio of the number (N) ofRBs of the E-UTRA carrier received signal strength indicator (RSSI)measurement bandwidth (e.g., system bandwidth) multiplied by the RSRPdivided by the RSSI, generally expressed as ‘N*RSRP/RSSI’. In general, agiven UE can measure/determine signal strength information such as, forexample, RSRP and/or RSRQ for a serving cell and/or non-serving cells(e.g., neighboring cells), if enabled. In certain embodiments, RSRPand/or RSRQ measurements for neighboring cells can be enabled for UE 112a-112 d. As used herein the terms ‘relative RSRP’ and ‘relativeinterference’ can be used interchangeably and can refer to a servingcell RSRP as measured by a given UE subtracted from a neighboring cellRSRP as measured by the UE.

It should be noted that any UE signal strength information can be usedamong various embodiments described within the scope of the presentdisclosure for determining and/or controlling UE uplink power controlparameters. In at least one embodiment, for example, for a 3Gdeployment, signal strength information can include Common Pilot Channel(CPICH) energy per chip to total PSD at the UE antenna (Ec/lo) and/orCPICH Received Signal Code Power (RSCP) as defined in 3GPP standards. Inanother embodiment, for example, for a WiFi deployment, signal strengthinformation can include Received Signal Strength Indicator (RSSI),Received Channel Power Indicator (RCPT), combinations thereof, or othersimilar signal strength information. Accordingly, although many of theexample embodiments discussed herein are described with reference toRSRP and/or RSRQ signal strength information, it should be understoodthat signal strength information as discussed for the variousembodiments described herein can cover a multitude of access networktypes including both 3GPP and non-3GPP access networks.

In certain embodiments, downlink channel quality indicator (CQI)reported by a UE can be used to determine downlink SINR by using the CQIreported for a given UE as a proxy for determining downlink SINR.Generally, the CQI reported by a UE may be used to determine theModulation and Coding Scheme (MCS) at which the cell radio to which theUE is connected needs to transmit packets to the UE such that the UEwill receive packets at a 10% Block Error Rate (BLER). If an AverageWhite Gaussian Noise (AWGN) channel is assumed for the UE, an SINR canbe determined that will lead to a 10% BLER based on the MCS chosen bythe cell radio for downlink transmissions to the UE via the PhysicalDownlink Shared Channel (PDSCH), which carries data transport blocks(e.g., RBs) to the UE. Generally, each MCS from which the cell radio canchoose for downlink transmissions can be mapped to one or more SINRvalues or a range of SINR values, thereby enabling SINR determinationsusing the MCS chosen for downlink transmissions. Although UEmanufacturers often implement different receivers, etc. for theirequipment, which can lead to non-one-to-one MCS to SINR mappings, CQIcan be used to determine an approximate SINR for a given UE based on theassumption that, as SINR increases for a UE, CQI can also increasebecause the UE can decode higher order modulation schemes while stayingwithin the 10% BLER threshold.

Under an assumption of approximate uplink and downlink symmetry for agiven UE, uplink or downlink SINR can be used for various embodimentsdescribed herein. MCS can also be selected for UE for uplinktransmissions. As provided by 3GPP standards (e.g., TS 36.111), MCS foruplink UE transmissions can include Quadrature Phase Shift Keying (QPSK)and Quadrature Amplitude Modulation (QAM) including 16QAM, 64QAM and256QAM with modulation order increasing from QPSK to 256QAM.

As illustrated FIG. 1A, UE 112 a-112 b may be located in relativeproximity within the coverage area of small cell radio 114 a, which maybe the serving or source cell radio for UE 112 a-112 b, as indicated bythe solid line indicating interconnection between UE 112 a-112 b andsmall cell radio 114 a. In various embodiments, UE 112 a may bedetermined by small cell radio 114 a to be a cell interior UE within thecoverage area of small cell radio 114 a and UE 112 b may be determinedto be a cell edge UE within the coverage area of small cell radio 114 a.UE 112 c may be located in relative proximity within the coverage areaof small cell radio 114 b, which may be the serving or source cell radiofor UE 112 c, as indicated by the solid line indicating interconnectionbetween UE 112 c and small cell radio 114 b. UE 112 c may be determinedby small cell radio 114 b to be a cell edge UE within the coverage areaof small cell radio 114 b. It should be understood, however, that thelocation of UE 112 a-112 c in relation to small cell radio 114 a-114 bis provided for illustrative purposes only and is not meant to limit thebroad scope of the present disclosure. It should be understood that UEscan be distributed anywhere within the coverage areas of small cellradios 114 a-114 b within the scope of the teachings of the presentdisclosure.

In some embodiments, determinations of whether a given UE is a cell edgeUE can be performed by a given serving small cell radio (e.g., smallcell radio 114 a) by determining the received power for an uplink signalfrom a given UE divided by the interference in the cell in comparison toan expected or target SINR threshold (Target_SINR_(CELL) _(_) _(EDGE))for cell edge UE. In some embodiments, the determination can include adividing RSRP of the serving cell as measured by the UE by uplink RSSIfor the UE minus RSRP of the serving cell radio and comparing the resultto the Target_SINR_(CELL) _(_) _(EDGE). For example, if(serving_cell_RSRP)/(RSSI−serving_cell_RSRP)<Target_SINR_(CELL) _(_)_(EDGE), then a given UE may be a cell edge UE. In various embodiments,Target_SINR_(CELL) _(_) _(EDGE) can be varied in a range fromapproximately 5 decibel (dB) to approximately 10 dB, depending onexpected interference and/or path loss for a small cell radio deploymentunder an assumption of at least two neighboring small cell radios andempirical data available.

In some embodiments, determination of whether a given UE is a cellinterior UE can be performed by a given serving small cell radio (e.g.,small cell radio 114 a) using a similar comparison in relation to anexpected or target SINR threshold (target_SINR_(CELL) _(_) _(INT)) forcell interior UE. For example, if(serving_cell_RSRP)/(RSSI−serving_cell_RSRP)>target_SINR_(CELL) _(_)_(INT), then a given UE may be a cell interior UE. In variousembodiments, target_SINR_(CELL) _(_) _(INT) can be varied in a rangefrom approximately 10 dB to approximately 15 dB, depending on expectedinterference and/or path loss for a small cell radio deployment andempirical data available.

In various embodiments, cell edge UE or cell interior UE determinationscan be facilitated using other information including, but not limitedto, using one or more of: a channel quality indicator (CQI) reported bythe UE for downlink communications (e.g., communications from the smallcell radio toward the UE) and/or a reference signal received quality(RSRQ) as measured by the UE and performing CQI and/or RSRQ comparisonsto a predetermined threshold.

In various embodiments, each small cell radio 114 a-114 b may managescheduling for uplink radio resources for uplink transmissions for eachcorresponding UE 112 a-112 c that the small cell radios respectivelyserve. Uplink radio resources may be those resources transmitted over anair interface by a particular UE (e.g., using one or more combinationsof transmitters and/or antenna(s)) to be received by its serving cellradio (e.g., using one or more combinations of receivers and/orantenna(s)). For example, in certain embodiments, assuming UE 112 a-112b are connected to and currently served by small cell radio 114 a, smallcell radio 114 a can schedule uplink resources for uplink transmissionsthat may be carried out by UE 112 a-112 b. In turn, UE 112 a-112 b canperform uplink transmissions as scheduled by small cell radio 114 a.Typically, uplink transmissions are scheduled via uplink grants that canbe communicated by a serving cell radio to a corresponding UE. Similaruplink transmissions can be scheduled for UE 112 c by small cell radio114 b and for UE 112 d by macro cell radio 116.

In certain embodiments, LTE architectures can support multi-user accessusing Orthogonal Frequency-Division Multiple Access (OFDMA), which is amulti-user version of the orthogonal frequency-division multiplexing(OFDM) digital modulation scheme. Multiple accesses are achieved inOFDMA by assigning subsets of subcarriers to individual users. OFDMAallows for simultaneous transmissions from several users served by aparticular cell radio. In certain embodiments, LTE architectures canalso support multi-user access using Single Carrier Frequency DivisionMultiple Access (SC-FDMA), which is similar to OFDMA, but includesadditional precoding.

Generally in LTE architectures, a given serving cell radio (e.g., smallcell radio 114 a) can schedule uplink transmissions for a given UE(e.g., UE 112 a) by scheduling physical resource blocks, generallyreferred to as resource blocks (RBs), that are to be transmitted by theUE according to one or more uplink grants, as noted above. For example,using one or more uplink grants, small cell radio 114 a can signal tothe UE, when it can transmit uplink RBs or resources toward small cellradio 114 a. Uplink grants are typically communicated to the UE via aphysical downlink control channel (PDCCH) maintained between the UE andthe serving cell radio. Typically, the PDCCH can be used to communicateinformation related to information downlink (DL) grant(s), uplink (UL)grant(s), power control, system configuration, random access, paging,etc. for UE.

An RB, as defined in 3GPP technical specification (TS) 36.211, istypically represented by a number of resource elements, each of whichcan be allocated within a symbol, for each of a particular subcarrier(e.g., frequency) that can be associated with a particular UE. An RB cangenerally be referred to as a ‘slot’ spanning 0.5 milliseconds (msec) ofa 1 msec subframe. Thus, there are typically two RBs in each 1 msecsubframe. The smallest unit of an RB is a resource element, whichrepresents one subcarrier by one symbol. Thus, a RB can be schematicallyrepresented as spanning a portion of frequencies of system bandwidth(e.g., depending on the number of subcarriers in the RB) across a spanof time (e.g., 0.5 msec) for each symbol included in the RB. For 4G/LTE,the number of subcarriers for an RB is 12, each spanning a 15 kilohertz(15 KHz subcarrier bandwidth), thus each RB represents a 180 KHz portionof system bandwidth. As system bandwidth can vary, such as, for example,between 1.25 megahertz (MHz) and 20 MHz, the number of available RBsthat can be scheduled or allocated across UEs can vary, respectivelybetween 6 and 100. Typically, a 10 MHz bandwidth corresponds to 50available RBs that can be allocated to UEs served by a particular cell.It should be understood that RBs can be uplink RBs or downlink RBs,depending on the device transmitting the RBs.

Referring to FIG. 1B, FIG. 1B is a simplified schematic diagramillustrating an example uplink RB 160 that can be used for uplinktransmissions in accordance with one potential embodiment of thecommunication system. Uplink RB 160 can represents a 0.5 msec slot 164of a 1 millisecond (msec) transmission time interval (TTI) for a numberof symbols 168 spread across a number of subcarriers 166. In variousembodiments, the number of subcarriers 166 is typically 12. In variousembodiments, the number of symbols 168 can depend on the cyclic prefixtype for uplink transmissions (e.g., 12 symbols for normal cyclic prefixor 14 for symbols for extended cyclic prefix). As noted, the smallestunit of a RB is a resource element, shown in FIG. 1B as resource element170, which represents one subcarrier 166 by one symbol 168.

Before detailing some of the operational aspects of FIG. 1A, it isimportant to understand common characteristics of uplink interferencethat can occur in mobile communication networks. The followingfoundation is offered earnestly for teaching purposes only and,therefore should not be construed in any way to limit the broadteachings of the present disclosure.

Uplink data (e.g., RBs) can be transmitted by a given UE (e.g., UE 112a) using a Physical Uplink Shared Channel (PUSCH), a Physical UplinkControl Channel (PUCCH) or a Physical Random Access Chanel (PRACH).Uplink transmissions by UE can cause interference, typically referred toas power spectral density (PSD) interference or interference PSD, to aparticular serving cell radio and/or to one or more neighboring cellradios. Interference, as represented herein using the symbol ‘/’, can bequantified as interference over thermal noise (IoT), which is the ratioof interference PSD to thermal noise PSD. Thermal noise PSD, as definedin 3GPP TS 26.214, is the white noise PSD on the uplink carrierfrequency multiplied by the uplink system bandwidth. As referred toherein in this Specification the terms ‘IoT’ and ‘interference’ may beused interchangeably.

As noted, uplink transmissions from a UE to its serving cell can causeinterference toward one or more neighboring cells. Interference causedto small cell deployments can include small cell to small cellinterference from neighboring small cells, and/or macro to small cellinterference from neighboring macro cells. In addition, cell edge UE insmall cell deployments can cause interference not only to other smallcells but also to surrounding macro cells (e.g., small cell to macrocell interference). For various embodiments described herein, it may beassumed that cell interior UE for small cell deployments may notcontribute in a significantly quantifiable amount to small cell to smallcell interference and/or to small cell to macro cell interference.

As referred to herein in this Specification, small cell to small cellinterference can be denoted using the term ‘I_(SMALL)(c)’, which mayrepresent the IoT due to other small cell UE for neighboring small cellradios as measured at a particular small cell radio ‘c’. In variousembodiments, I_(SMALL)(c) can be assumed to not exceed approximately 3dB over noise; thus, I_(SMALL)(c) can be set to 3 dB over noise forvarious equations as described herein for various embodiments. However,it should be understood that I_(SMALL)(c) can be other values. Asreferred to herein in this Specification, macro cell to small cellinterference can be denoted using the term ‘I_(MACRO)(c)’, which mayrepresent the IoT due to macro UEs as measured at a particular smallcell radio ‘c’ and may be expressed as dB over noise.

For example, cell edge UE 112 c served by small cell radio 114 b cancause interference toward small cell radio 114 a, shown in FIG. 1A asI_(SMALL)(114 a), which may represent the IoT due to cell edge UE 112 cas measured at small cell radio 114 a. Cell edge UE 112 b served bysmall cell radio 114 a can cause interference toward small cell radio114 b, shown in FIG. 1A as I_(SMALL)(114 b), which may represent the IoTdue to cell edge UE 112 b as measured at small cell radio 114 b.Further, macro UE 112 d may also cause interference toward small cellradio 114 a and/or small cell radio 114 b. The IoT due to macro UE 112 das determined by small cell radio 114 a is represented as I_(MACRO)(114a). As noted, macro UE 112 d may also cause interference toward smallcell radio 114 b, however, this is not shown in FIG. 1A in order toillustrate other features of communication system 100.

As noted, cell edge UE for small cell deployments can also causeinterference towards surrounding macro cells (e.g., small cell to macrocell interference). As referred to herein in this Specification, smallcell to macro cell interference can be denoted using the term‘IoT_(SMALL->MACRO)’, which may represent the IoT due to small cell UEstoward neighboring macro cell radio(s). In various embodiments, onedominant macro cell radio (e.g., macro cell radio 116) may be determinedto be in the vicinity of a cluster or group of neighboring small cellradios (e.g., small cell radios 114 a-114 b). In various embodiments,the determination of a dominant macro cell radio can be based onreal-time measurements, deployment, operator configuration, combinationsthereof or the like.

For LTE, 3GPP specifications define different interference mitigationschemes such as, for example, interference reduction and inter cellinterference coordination (ICIC). Interference reduction is typicallyassociated with optimizing coverage and capacity for a network. ICIC istypically associated with the management of radio resources to mitigateinter cell interference. In the frequency domain, ICIC is often used tomanage the allocation of RBs between cells in order to coordinate theuse of frequency domain resources. In particular, frequency domain ICICcan be used to mitigate inter cell interference with neighboring cellsfor UEs located at the edge of a coverage area of a given serving cell(e.g., cell edge UEs) that may have resources allocated thereto, whichcan interfere with the neighboring cells.

In addition to ICIC techniques, managing uplink UE power control forsmall cell deployments, as provided by various embodiments ofcommunication system 100, can also be used to mitigate adverse effectsof small cell to small cell interference and/or macro cell to small cellinterference. In particular, uplink power control techniques as providedby various embodiments of communication system 100 can be used maximizesmall cell uplink SINR for small cell deployments while maintainingand/or limiting interference to neighboring macro cell deployments.

Generally, uplink power control for UE transmissions involves settingopen loop power control parameters for a cell radio. A first powercontrol parameter, often identified to as ‘P₀’ in 3GPP specifications,generally identifies a transmit power offset value for UE uplinktransmissions and a second power control parameter, often identified as‘a’ in 3GPP specifications, generally identifies an amount of path loss(PL) between UE and a serving cell radio that is inverted for UEtransmissions toward the serving cell. For small cell deployments, it isgenerally desirable to scale a as UE move further from their servingsmall cell radio. For example, as UE move into the cell edge of a smallcell radio, it is generally desirable to increase a in order to increasethe amount of downlink power inverted by the UE for uplink transmissionsin order to maintain an expected or target SINR for cell edge UE. Invarious embodiments, a can range from zero (0), in which case UEtransmit power is controlled solely by P₀, to one (1), in which case theserving small cell radio downlink power is fully inverted for UE uplinktransmit power. Yet, increasing a can cause interference caused by celledge UE toward neighboring small cells and/or neighboring macro cells(e.g., little interference may be caused if a small cell radio isdeployed near the edge of a macro cell coverage area, but greaterinterference may be caused if a small cell radio is deployed near theinterior of a macro cell coverage area).

In current deployments, uplink UE power control typically assumes: 1)that power control for all uplink transmissions is provided using acommon algorithm and/or 2) that small cells provide power control tomeet macro cell constraints (e.g., to limit small cell to macro cellinterference), yet current deployments often apply a uniform powerrestriction across all UE (e.g., cell interior and cell edge) served bya given small cell radio. The first assumption typically used for uplinkpower control in current deployments is inapplicable to deployments inwhich small cell and macro cell deployments overlap because macro cellpower is often fixed, which can lead to limitations being on small celluplink SINR in order to meet small cell to macro cell interferenceconstraints. The second assumption typically used for uplink powercontrol in current deployments in which a uniform power restriction isapplied across all small cell UE can lead to suboptimal uplink SINR forcell edge UE for small cell deployments that may be at the edge of amacro cell radio coverage area for a given macro cell radio but inreality may cause little interference toward the macro cell radio.

In accordance with at least one embodiment, communication system 100 isconfigured to provide a system and method to facilitate small celluplink power control through coordination and management of uplink powercontrol parameters for small cell radios 114 a-114 b via centralmanagement system 122. In various embodiments, the method provided bycommunication system 100 may facilitate small cell uplink power controlthrough optimizing power control parameters for small cell uplink UEtransmissions through interference coordination between small cellradios 114 a-114 b and central management system 122 as well as throughinterference coordination between small cell radio 114 a and small cellradio 114 b. In various embodiments, the method provided bycommunication system 100 can be carried out using one or more hardwareprocessors configured for small cell radios 114 a-114 b and/or centralmanagement system 122.

During operation, in at least one embodiment, the method provided bycommunication system 100 may provide for determining one or more set(s)of optimized power control parameters, P₀ and α, for small cell radios114 a-114 b to set absolute uplink power levels for small cell UE servedby small cell radios 114 a-114 b that may overcome interference causedtoward the small cell radios from UE associated with a given macro cellradio (e.g., UE 112 d associated with macro cell radio 116) whilelimiting interference caused by the small cell UE towards the macro cellradio. In various embodiments, communication system 100 can provide fordetermining one or more set(s) optimized power control parameters forsmall cell radios 114 a-114 b using various operational architectures.

First Operational Architecture

Under a first operational architecture, determining one or more set(s)of optimized power control parameters can include one or more of smallcell radios 114 a-114 b determining one or more set(s) of candidatepower control parameters (e.g., one or more set(s) of P₀ and α) based ona first interference constraint that is associated, at least in part,with interference caused toward each small cell radio 114 a-114 b by oneor more macro cell UE. In general, the first interference constraint canbe used to determine set(s) of candidate power control parameters thatmay provide for small cell UE uplink power levels that may overcome theinterference caused by macro UEs towards the small cell radio(s), whilelimiting interference that may be caused toward neighboring small cellradio(s). The first interference constraint is described in more detailbelow with regard to Equation 1.

The one or more set(s) of candidate power control parameters can becommunicated to central management system 122. Under the firstoperational architecture, central management system 122, via centralpower management module 150, can use the one or more set(s) of candidatepower control parameters to determine one or more set(s) of optimizedpower control parameters according to a second interference constraintthat provides for limiting the maximum interference caused toward macrocell radio 116 according to a maximum interference threshold for‘IoT_(SMALL->MACRO)’, denoted herein as ‘IoT_(SMALL->MACRO) ^(MAX)’. Thesecond interference constraint is described in more detail below withregard to Equation 2.

Central management system 122 can communicate the one or more set(s) ofoptimized power control parameters to small cell radios 114 a-114 b,each of which may then set relative power levels for each correspondingUE served thereby (e.g., UE 112 a-112 b for small cell radio 114 a, UE112 c for small cell radio 114 b) according to various ICICconsiderations to provide interference mitigation between the small cellradios.

Various embodiments that can be associated with the first architecturein which one or more small cell radio(s) 114 a-114 b can determine oneor more set(s) of candidate power control parameters are now discussed.In various embodiments, the first interference constraint, as discussedin further detail below via Equation 1, can be applied to both cellinterior UE and cell edge UE served by a given small cell radio ‘c’ inorder to determine one or more set(s) of candidate power controlparameters associated with small cell radio ‘c’. In various embodiments,the first interference constraint can be applied to cell edge UE andcell interior UE using corresponding target SINR values received fromcentral management system 122 and/or according to an indication receivedfrom central management system 122 (e.g., to decrease or increasecorresponding target SINR value(s)).

In some embodiments, each of one or more small cell radio 114 a-114 bcan be tasked or selected to calculate one or more set(s) of candidatepower control parameters to feed to central management system 122. Invarious embodiments, each of a set of candidate power controlparameters, P₀ and α, as calculated by each of a given small cell radiocan be indexed such that central management system 122 can associateeach of the given set of power control parameters to the appropriatesmall cell radio. In some embodiments, cell identity (ID) can be used toindex each P₀ and α. In various embodiments, cell ID can include aPrimary Scrambling Code (PSC) (e.g., for 3G deployments), Physical CellIdentifier (PCI) (e.g., for 4G deployments), combinations thereof or thelike.

In some embodiments, a particular small cell radio can be tasked orselected to provide one or more set(s) of candidate power controlparameters to central management system 122. For example, a small cellradio that is determined to experience the highest interference frommacro UEs associated with a dominant macro cell radio can be selected todetermine one or more set(s) of candidate power control parameters tocommunicate to central management system 122.

Upon determining the one or more set(s) of candidate power controlparameters, the small cell radio(s) may generate one or more messagestoward central management system 122 including the one or more set(s) ofcandidate power control parameters. Based on the one or more set(s) ofcandidate power control parameters, central management system 122, viacentral power management module 150, can determine a set of optimizedpower control parameters according to a second interference constraintthat provides for limiting the maximum interference caused toward macrocell radio 116 according to the maximum interference threshold‘IoT_(SMALL→MACRO) ^(MAX)’. In general, central management system 122may determine whether a given set of candidate power control parametersprovide for meeting the second interference constraint such that anaverage of a sum of expected interference that may be caused by smallcell UE toward the macro cell radio remains below the maximuminterference threshold ‘IoT_(SMALL→MACRO) ^(MAX)’. The secondinterference constraint is described in more detail below with regard toEquation 2.

For the first operational architecture, the generation of candidatepower control parameters by small cell radio(s) 114 a, 114 b can beperformed using different techniques. In some embodiments, one or moresmall cell radio 114 a-114 b may calculate one set of candidate powercontrol parameters that meet the first interference constraint and maygenerate one or more messages communicating the candidate power controlparameters to central management system 122. In turn, central managementsystem 122 may determine whether the set of candidate power controlparameters provide for meeting the second interference constraint. If itis not met, central management system 122 may task the one or more smallcell radio 114 a-114 b to reduce the cell interior UE SINR thresholdvalue and/or the cell edge UE SINR threshold value to calculate a newset of candidate power control parameters. In various embodiments, thereduction can be in whole or fractional values.

In some cases, for example, the cell interior SINR value alone can bereduced if the current cell interior SINR value is greater than thecurrent cell edge SINR value. In other cases, both the cell interiorSINR value and the cell edge SINR value can be reduced if the currentcell interior SINR value is equal to the current cell edge SINR value.This iterative operation may continue until central management system122 determines one or more set(s) of optimized power control parametersthat meet the second interference constraint, in which case centralmanagement system 122 can generate one or more messages toward each ofsmall cell radio 114 a-114 b including the set(s) of optimized powercontrol parameters in order for the small cell radios to set absoluteuplink power levels for UE served thereby.

In other embodiments, one or more small cell radio 114 a-114 b maycalculate multiple sets of candidate power control parameters that meetthe first interference constraint according to different combinations ofcell interior UE SINR threshold values and cell edge UE SINR thresholdvalues and may generate one or more messages communicating the sets ofcandidate power control parameters to central management system 122. Inturn, central management system 122 may search the sets of candidatepower control parameters in order to determine one or more set(s) ofoptimized power control parameters that meet the second interferenceconstraint. In various embodiments, multiple sets of candidate powercontrol parameters may be found to meet the second interferenceconstraint, in which cases central management system 122 may determinemultiple sets of optimized power control parameters. Upon determiningthe one or more set(s) of optimized power control parameters, P₀ and α,central management system 122 can generate one or more messages towardeach of small cell radio 114 a-114 b including the one or more set(s) ofoptimized power control parameters to set absolute uplink power levelsfor UE associated with the small cell radios.

In various embodiments, upon receiving set(s) of optimized power controlparameter(s), each small cell radio 114 a-114 b may set relative powerlevels for each corresponding UE served thereby (e.g., UE 112 a-112 bfor small cell radio 114 a, UE 112 c for small cell radio 114 b)according to various ICIC considerations to provide interferencemitigation between the small cell radios. Various ICIC considerationsassociated with setting relative uplink UE power levels according tovarious embodiments are described more detail below. In variousembodiments, the system and method provided by communication system 100may provide for efficient interference mitigation between small cell UEswhile at the same time maintaining just enough power to overcomeinterference caused by macro cell UEs in the vicinity of the small cellUEs.

Second Operational Architecture

Under a second operational architecture, determining one or more set(s)of optimized power control parameters can include one or more small cellradios 114 a-114 b determining an estimated path loss (PL) with adominant macro cell radio and determining an estimated path loss withone or more UE served by the one or more small cell radios. Similar tothe various embodiments discussed for the first operationalarchitecture, the second operational architecture can also be varied inthat each small cell radio can be tasked or selected to determineestimated path loss information or a particular small cell radio (e.g.,that is determined to experience the highest interference from UEsassociated with a dominant macro cell radio) can be tasked withdetermining the estimated path loss information.

The one or more small cell radios 114 a-114 b can send the estimatedpath loss information to central management system 122. In variousembodiments, the path loss information can be indexed by cell ID. Uponreceiving the path loss information, central management system 122 candetermine one or more set(s) of optimized power control parameters.Similar to the first operational architecture, under the secondarchitecture, central management system 122 can communicate the one ormore set(s) of optimized power control parameters to small cell radios114 a-114 b, each of which may then set relative power levels for eachcorresponding UE served thereby (e.g., UE 112 a-112 b for small cellradio 114 a, UE 112 c for small cell radio 114 b) according to variousICIC considerations to provide interference mitigation between the smallcell radios.

Under the second operational architecture, central management system122, via central power management module 150, can determine the one ormore set(s) of optimized power control parameters based on applicationof both the first and second interference constraints. In essence,central management system 122 can use the estimated path lossinformation to generate one or more set(s) of candidate power controlparameters using the first interference constraint and can thendetermine one or more set(s) of optimized power control parameters whichmeet the second interference constraint. Thus, the second operationalarchitecture differs from the first operational architecture in thatcalculations according to the first and second interference constraintscan be localized to central management system. In various embodiments,the second operation architecture may provide for reduced signalingbetween central management system 122 and one or more small cell radios114 a-114 b over the first operational architecture in order todetermine one or more set(s) of optimized power control parameters.

The second operational architecture can also provide for differentoperating variations. In some embodiments, central management system122, via central power management module 150, can calculate, in aniterative manner, a set of candidate power control parameters that meetthe first interference constraint using the path loss information andSINR threshold values (e.g., for cell edge and cell interior UEs) andcan then determine whether the candidate power control parameters meetthe second interference constraint. This iterative calculate and checkprocessing can continue by adjusting the SINR threshold values (e.g.,increasing or decreasing in varying increments) until one or more set(s)of optimized power control parameters are determined. In embodiments,the one or more set(s) of candidate power control parameters and the oneor more set(s) of optimized power control parameters can be indexed tocorrespond to particular small cell radios or can be calculated as ageneral set, applicable to all small cell radios in a particular smallcell deployment.

In some embodiments, central management system 122, via central powermanagement module 150, can determine multiple sets of candidate powercontrol parameters that meet the first interference constraint using thepath loss information across different SINR threshold values. Once themultiple sets of candidate power control parameters are determined,central management system can search the sets to determine one or moreset(s) of optimized power control parameters.

Different variations of estimated path loss information can also becalculated by one or more small cell radios 114 a-114 b. In someembodiments, a maximum estimated path loss among cell edge UE and amaximum estimated path loss among cell interior UE served by aparticular small cell radio can be determined by the particular smallcell radio. The particular small cell radio can then communicate themaximum estimate path loss among cell edge UE and the maximum estimatedpath loss among cell interior UE to central management system 122, whichcan determine one or more set(s) of optimized power control parametersas discussed herein

In various embodiments, a function ‘PL_(UE)(c,u)’ can be used tocalculate path loss between a given UE ‘u’ and a given small cell radio‘c’ (either a serving or a neighboring small cell radio) according tothe expression: ‘RSRP_(u)=TX_Power(c)−PL_(UE)(c,u)’ where ‘RSRP_(u)’ isthe RSRP as reported to small cell radio ‘c’ by UE ‘u’ and ‘TX_Power(c)is the transmit power of small cell radio ‘c’ (known by the small cellradio). In various embodiments, another function ‘MAX_(uεU(c))PL_(UE)(c,u)’ may be used to determine the maximum path loss (PL) for agiven UE ‘u’ among a set of UEs ‘U(c)’ (e.g., cell interior UE or celledge UE) served by a given small cell radio ‘c’ (e.g., small cell radio114 a, 114 b). Thus, for all UE served by a given small cell radio, thegiven small cell radio can determine a set of one or more UE that may becell edge UE (e.g., based on comparisons to a target cell edge UE SINRthreshold) and may determine from that set a corresponding cell edge UEexhibiting a maximum path loss with the small cell radio. A similarmaximum path loss determination/calculation can also be performed todetermine a maximum path loss among cell interior UE served by the smallcell radio.

In some embodiments, estimated path loss information for each UE servedby a given small cell radio can be communicated to central managementsystem 122, which can filter (e.g., to determine maximum path loss forany UE, cell edge UE or cell interior UE served by the small cell radio)or process the estimated path loss information in order to determine oneor more set(s) of optimized power control parameters as discussed forthe various embodiments described herein.

In various embodiments, the path loss from a given dominant macro cellradio (e.g., macro cell radio 116) to a given small cell radio ‘c’(e.g., small cell radio 114 a, 114 b) can be represented as‘PL_(macro)(c)’. In various embodiments, certain assumptions can bemade, which may aid in determining an estimated macro path loss for agiven small cell radio ‘c’. In some embodiments, one assumption mayinclude assuming that the macro path loss, ‘PL_(macro) (C)’, from agiven macro cell radio to a given small cell radio ‘c’ may beapproximately the same as the path loss from UE associated with thesmall cell radio to the macro cell radio. Thus, in some embodiments,‘PL_(macro)(c)’ may be based on measurement reports (e.g., RSRPmeasurement reports) received from UE served by the small cell radio. Inother embodiments, ‘PL_(macro)(c)’ may be based on network listenoperations performed by a given small cell radio (e.g., the small cellradio ‘listening’ for over-the-air transmissions from neighboring smallcell radios via its internal receiver).

In various embodiments, another assumption can include that there existsone dominant macro cell radio in the vicinity of a cluster or group ofneighboring small cell radios. In various embodiments, it is assumedthat small cell radios 114 a-114 b are provided or configured with cellID information (e.g., PSC, PCI, Cell Global Identifier (CGI), E-UTRANCell Global Identifier (ECGI), etc.) to enable identification of adominant macro cell radio via UE measurement reports and/or networklisten operations.

Interference Constraints

A further analysis of the first and second interference constraints isnow provided. It should be understood that the first and secondinterference constraints can be applied under both the first and secondoperational architectures. Turning to the first interference constraint,the first interference constraint may, in various embodiments, relateinterference caused toward one or more small cell radios 114 a-114 b byone or more macro cell UE (e.g., macro UE 112 d) in order to determineone or more set(s) of candidate power control parameters that mayprovide for small cell UE transmit power levels that may overcome theinterference caused by the one or more macro UE, while limitinginterference that may be caused toward neighboring small cell radio(s).The first interference constraint can be represented as shown below inEquation 1.

P ₀+(α−1)MAX_(uεU(c)) PL _(UE)(c,u)≧Total_Interf+Δ  Eq. 1

For Equation 1, the term ‘Total_Interf’ can represent the sum ofI_(MACRO)(c) (e.g., in units of dB over noise) plus I_(SMALL)(c) (e.g.,assumed to be 3 dB over noise) converted to units of dB such thatTotal_Interf can be added to delta ‘Δ’. For example, in variousembodiments, a function ‘f(x)’ can be defined to convert dB over noiseto milliwatts (mW) such that ‘f(x)=10^((x/10))*noise(mW)’ such that‘Total_Interf=10*LOG₁₀[f(I_(MACRO)(c))+f(3)]’. In various embodiments, Δmay be set to a target SINR threshold value for cell edge UE or cellinterior UE for small cell radio ‘c’.

As noted, I_(MACRO)(c) is the interference toward cell ‘c’ caused by oneor more UE associated with a dominant macro cell radio (e.g., macro cellradio 116). In various embodiments, when there is no coordinationbetween macro cell radios and small cell radios in a deployment, UE maybe associated with a neighboring macro cell radio when it is measured tobe even a few (e.g., 3 to 5) dB stronger than small cell UE, which meansthat the path loss to a small cell radio for macro cell UE can be about20 dB less than the path loss to the corresponding macro cell radio. Invarious embodiments, the average IoT caused to a given small cell radio‘c’ should be smaller than that caused by macro UE transmitting at alltimes since not all UE associated with a given macro cell radio will beclose to the same small cell radio for a small cell deployment.

In various embodiments, I_(MACRO)(c) for a given small cell radio ‘c’can be calculated based on the total average interference measured atcell ‘c’ minus the total small cell UE interference caused byneighboring small cells. For example, in some embodiments, each smallcell radio (e.g., small cell radios 114 a-114 b) can compute an averageinterference that UE served thereby can cause to one or more neighboringsmall cell radio(s). In various embodiments, an average interferencecaused toward a neighboring small cell radio(s) by UE served by givensmall cell radio ‘c’ can be based on determining a path loss to a givenneighboring small cell radio in combination with the UE transmit powerand number of resources assigned to each UE served by small cell radio‘c’. In various embodiments, path loss toward a given neighboring smallcell radio for a particular UE (e.g., PL_(UE)(c,u)) can be calculatedvia measurement reports communicated to small cell radio ‘c’.

Each small cell radio 114 a-114 b can report the average interferencecaused toward each of one or more neighboring cell(s) to centralmanagement system 122 via one or more messages generated by small cellradio 114 a-114 b. For example, small cell radio 114 a can report theaverage interference caused toward neighboring small cell radio 114 band small cell radio 114 b can report the average interference causedtoward small cell radio 114 a. Based on the reported interference causedto each neighboring small cell radio, central management system 122 canthen calculate the interference caused toward each neighboring smallcell radio in the small cell deployment based on the sum ofinterferences as reported by each of the small cell radios in thedeployment for each corresponding neighboring small cell radio.

In some embodiments, central management system 122 can report to eachsmall cell radio 114 a-114 b the total small cell UE interference causedtoward each small cell radio by each of its neighboring small cellradio(s) present in the small cell radio deployment. In turn, each smallcell radio can determine interference caused thereto from macro UEs bysubtracting the total small cell UE interference caused thereto from thetotal average interference measured at the small cell radio. Thus, invarious embodiments, I_(MACRO)(c) can be determined based on thefollowing equation such thatI_(MACRO)(c)=total_avg_interf(c)−total_small_cell_interf(c), wheretotal_avg_interf(c) is the total average interference as measured acrosstime and frequency at small cell radio ‘c’, andtotal_small_cell_interf(c) is the total small cell interference causedtoward small cell radio ‘c’ by one or more neighboring small cellradio(s).

In some embodiments, each small cell radio 114 a-114 b can report theaverage interference caused thereto from UE associated with macro cellradio 116 to central management system 122. In some embodiments, centralmanagement system 122 can use the report macro interference I_(MACRO)(c)for each small cell radio to determine a small cell radio experiencing ahighest interference from UE associated with macro cell radio 116 (e.g.,if central management system 122 is configured to task the small cellradio experiencing the highest macro UE interference to calculate one ormore set(s) candidate power control parameters.

In other embodiments, central management system 122 can calculateI_(MACRO)(c) for each small cell radio 114 a-114 b based on the averageinterference caused to neighboring small cell radios that may bereported to central management system. In various embodiments,estimations of I_(MACRO)(c) can be calculated in real-time or estimatedoff-line based on field experience, operator configuration, combinationsthereof or the like.

In various embodiments, A can be set to a given Target_SINR_(CELL) _(_)_(EDGE) threshold value or a given Target_SINR_(CELL) _(_) _(INT)threshold value in order to create a system of equations for the firstinterference constraint such that a candidate set of P₀ and α can becalculated for the given small cell ‘c’. The system of equations can berepresented as follows according to Equation System 1 in whichTarget_SINR_(CELL) _(_) _(EDGE) and Target_SINR_(CELL) _(_) _(INT) issubstituted for Δ for each equation in Equation System 1.

P ₀+(α−1)MAX_(U) _(_) _(CELL) _(_) _(EDGE) PL_(UE)(c,u_cell_edge)≧Total_Interf+Target_SINR_(CELL) _(_) _(EDGE)

P ₀+(α−1)MAX_(U) _(_) _(CELL) _(_) _(INT) PL_(UE)(c,u_cell_int)≧Total_Interf+Target_SINR_(CELL) _(—INT)   EquationSystem 1:

In various embodiments, based on the system of equations shown inEquation System 1, one or more set(s) of candidate power controlparameters (e.g., depending on configuration) can be determined for agiven small cell radio ‘c’ (e.g., as determined by one or more smallcell radio(s) 114 a-114 b or as determined by central management system122). In some embodiments, if ICIC and/or sub-band scheduling areprovided in communication system 100, the right-hand side of eachequation can be replaced by the lowest interference expected for a givensub-band or several constraints can be used based on the lowestinterference and the average interference for a given sub-band.

In some embodiments, adaptations of Equation 1 for cell edge UE can alsobe used to estimate the highest interference caused by UE in one smallcell to another small cell, denoted herein as ‘I_(HIGH)’. For example,in some embodiments, an average I_(HIGH) for a small cell deployment canbe determined according using the equation:P₀+αMAX_(c′)MAX_(uεU(c′))[PL(c′,u)−PL(c,u)] where the term c prime (c′)represents all small cells radios other than small cell radio ‘c’.

Turning to the second interference constraint, the second interferenceconstraint may, in various embodiments, provide for limiting the maximuminterference caused towards a given dominant macro cell radio (e.g.,macro cell radio 116) by UE associated with one or more neighboringsmall cell radios (e.g., small cell radio 114 a-114 b) to constrainsmall cell UE transmit power levels. The second interference constraintcan be represented as shown below in Equation 2.

$\begin{matrix}{{\Sigma_{c}{\frac{1}{{U(c)}}\left\lbrack {\Sigma_{u \in {U{(c)}}}{{dbmToLin}\left( {{P_{0}(c)} - {{PL}_{macro}(c)} + {{\alpha (c)}{{PL}_{UE}\left( {c,u} \right)}}} \right)}} \right\rbrack}} \leq {IoT}_{{small}->{macro}}^{\max}} & {{Eq}.\mspace{11mu} 2}\end{matrix}$

In general, Equation 2 can be used by central management system 122, viacentral power management module 150, to determine whether an average ofa sum of expected interference that may be caused toward a given macrocell radio (e.g., macro cell radio 116) by small cell UE associated withone or more neighboring small cell radios (e.g., UE associated withsmall cell radios 114 a-114 b), for a given set of candidate powercontrol parameters P₀(c) and α(c) (e.g., as calculated by one or moresmall cell radio(s) ‘c’ or by central management system 122), exceeds agiven threshold level of maximum interference that can be caused towardthe macro cell radio, denoted herein as ‘IoT_(SMALL→MACRO) ^(MAX)’. Invarious embodiments, the threshold level ‘IoT_(SMALL→MACRO) ^(MAX)’ thatmay be caused by neighboring small cell radio UE towards a given macrocell radio (e.g., macro cell radio 116) can be determined on the basisof the total IoT that would be caused toward a given macro cell radiowithout considering small cell UE interference. In various embodiments,‘IoT_(SMALL→MACRO) ^(MAX)’ may be set such that IoT at the macro cellradio is at a given level, say, from 6 dB to 9 dB. For example, if thetotal IoT that would be caused toward a given macro cell radio is 6 dB,then the threshold level for ‘IoT_(SMALL→MACRO) ^(MAX)’ may be set toapproximately 3 dB. In another example, if the existing IoT for a givenmacro cell radio (without small cell interference) is measured, thetotal IoT constraint can be used to determine the threshold level for‘IoT_(SMALL→MACRO) ^(MAX)’.

For Equation 2, the term ‘dbmToLin’ may represent a function that mayconvert decibel milliwatts (dBm) to milliwatts (mW). In variousembodiments, certain assumptions can be made for Equation 2, which mayaid in simplifying calculations for determining whether the secondinterference constraint may be met (e.g., whether an expected maximuminterference that may be caused by small cell UE towards a given macrocell radio is below the threshold level) for a given set of candidatepower control parameters. As discussed above, in some embodiments, oneassumption may include assuming that the macro path loss,‘PL_(macro)(c)’, from a given macro cell radio to a given small cellradio ‘c’ may be approximately the same as the path loss from UEassociated with the small cell radio to the macro cell radio. In someembodiments, another assumption can include that there exists onedominant macro cell radio in the vicinity of a cluster or group ofneighboring small cell radios.

In some embodiments, another assumption for Equation 2 can include anassumption that P₀(c)=P₀ for all neighboring small cell radios in agroup or cluster. In still other embodiments, a different assumption forEquation 2 can include an assumption that a given small cell radio ‘c’may allow for a UE specific value of P₀(c,u) for UE u associated withthe small cell radio. In some embodiments, the term ‘α(c)PL_(UE)(c,u)’can be determined based on deployment parameters, field data and/orreal-time statistics averaged over a sufficient time period. In variousembodiments, a sufficient time period might be an order of time scalesat which UE distributions might change (e.g., in order of minutes). Forexample, UE distributions can change rapidly or slowly depending on anumber of small cell deployment variations including, but not limitedto, time of day, fixed or mobile deployments (e.g., stationarydeployments such as buildings, etc. or mobile environments such assubways, trains, autos, etc.), deployment type (e.g., residential(single family and/or multi-family), commercial, etc.), combinationsthereof or the like.

As discussed for the various embodiments provided herein, upondetermining one or more set(s) of optimized power control parametersthat meet the second interference constraint, central management system122 can generate one or more messages toward each of small cell radio114 a-114 b including the one or more set(s) of optimized power controlparameters to set absolute uplink power levels for UE associated withthe small cell radios. Upon receiving set(s) of optimized power controlparameter(s), each small cell radio 114 a-114 b may set relative powerlevels for each corresponding UE served thereby (e.g., UE 112 a-112 bfor small cell radio 114 a, UE 112 c for small cell radio 114 b)according to various ICIC considerations to provide interferencemitigation between the small cell radios.

In various embodiments, UE specific power control can be provided underan ICIC framework such that uplink UE transmit power may be set to theminimum of one of: 1) P^(max), which may be a maximum capable transmitpower for the UE; 2) a transmit power such that the interference PSD ata neighboring small cell radio is no higher than the average IoT on agiven RB minus some target or expected cell edge UE SINR (e.g.,target_SINR_(CELL) _(_) _(EDGE)); or 3) an average UE PSD for a givensmall cell radio based on application of the second interferenceconstraint to UE power levels set for the small cell radio, which can beRB specific. A given RB ‘r’ that a UE is scheduled to transmit on canaffect its constraint on the maximum PSD in setting UE transmit powerlevel; thus, in various embodiments, a local optimization of UE transmitpower level can be adjusted according to RB scheduling for UE served bysmall cell radios 114 a-114 b within an ICIC framework.

For the various embodiments described herein, implementing small cellspecific power control can be provided by setting ‘Delta-MCS-enabled’ (acommon small cell radio configuration setting) for one or more of smallcell radios 114 a-114 b to a FALSE setting. Setting ‘Delta-MCS-enabled’to a FALSE setting implies that transmit PSD for UE served by a givensmall cell radio may remain constant irrespective of the MCS assignedthereto. Under this setting, an optimized value of P₀ and an optimizedvalue of a may be determined using the two-constraint basis as describedherein. In various embodiments, P₀ may be set such that a UE on theborder of a coverage area transmits at a maximum power (e.g., small aimplies a large P₀ and vice-versa) and a can be set based on a pair ofconsiderations such that at a maximum value of a cell interior UEs(e.g., Signal-to-Noise Ratio (SNR) greater than 20-25 dB whentransmitting at max power) should be received at an SINR of at least 15dB and at a minimum value of a cell interior UEs and cell edge UEs maybe received within about 15 dB (e.g., the exact value can depend on thede-sense properties of baseband for the UEs) of each other. In variousembodiments, an advantage of using ‘Delta-MCS-enabled’ set to FALSE maybe that with a same UE transmission power, MCS can be varied to maximizespectral efficiency.

Turning to FIGS. 2A-2C, FIGS. 2A-2C are simplified block diagramsillustrating example details of various elements that can be associatedwith communication system 100 in accordance with one or moreembodiments. FIG. 2A is a simplified block diagram illustrating exampledetails that can be associated with central management system 122 inaccordance with one embodiment of communication system 100. FIG. 2B is asimplified block diagram illustrating example details that can beassociated with small cell radio 114 a in accordance with one embodimentof communication system 100. FIG. 2C is a simplified block diagramillustrating example details that can be associated with UE 112 a inaccordance with one embodiment of communication system 100.

Although FIG. 2B describes example features related to small cell radio114 a, it should be understood that the example features as describedfor small cell radio 114 a can also be provided with respect to smallcell radio 114 b. Similarly, although FIG. 2C describes example featuresrelated to UE 112 a, it should be understood that the example featuresas described for UE 112 a can also be provided with respect to UE 112b-112 d.

Referring to FIG. 2A, central management system 122 can include centralpower management module 150, a central management system storage 204, atleast one processor 212 and at least one memory element 214. In at leastone embodiment, at least one processor 212 is at least one hardwareprocessor configured to execute various tasks, operations and/orfunctions of central management system 122 as described herein and atleast one memory element 214 is configured to store data associated withcentral management system 122. In at least one embodiment, central powermanagement module 150 is configured to implement various small celluplink power control operations as described herein for centralmanagement system 122, including, but not limited to, determining one ormore set(s) of candidate power control parameters P₀ and a according toEquation System 1 based on the first interference constraint asrepresented by Equation 1 (e.g., for the second operationalarchitecture), determining one or more set(s) of optimized power controlparameters that meet the second interference constraint (e.g., for thefirst or second operational architectures), determining a total sum ofsmall cell UE interference for each small cell radio 114 a-114 b and/orother operations as described herein. In various embodiments, centralmanagement system storage 204 can be configured to store informationassociated with various small cell uplink power control operations asdescribed herein including, but not limited to, storing one or moreset(s) of candidate power control parameters (e.g., as reported tocentral management system 122 by one or more small cell radio 114 a, 114b or as determined by central management system 122); storing an averageinterference of caused by each small cell radio toward neighboring smallcell radio(s); and/or storing other small cell uplink power controlinformation.

Referring to FIG. 2B, small cell radio 114 a can include a transmitter220, a receiver 222, one or more antenna(s) 224, an uplink powermanagement module 226, a small cell radio storage 228, at least oneprocessor 242 and at least one memory element 244. In at least oneembodiment, at least one processor 242 is a hardware processorconfigured to execute various tasks, operations and/or functions ofsmall cell radio 114 a as described herein and at least one memoryelement 244 is configured to store data associated with small cell radio114 a. In at least one embodiment uplink power management module 226 isconfigured to implement various small cell uplink power control and/orresource management operations as described herein for small cell radio114 a, including, but not limited to, determining/calculating one ormore set(s) of candidate power control parameters P₀ and α according toEquation System 1 based on the first interference constraint asrepresented by Equation 1 (e.g., for the first operationalarchitecture), determining estimate UE and macro path loss information(e.g., for the second operational architecture) and/or setting relativeUE power levels according to absolute power levels that may be based onoptimized power control parameters received from central managementsystem 122.

In various embodiments, small cell radio storage 228 can be configuredto store information associated with various small cell uplink powercontrol and/or resource management operations as described hereinincluding, but not limited to, total small cell UE interference, whichcan be received from central management system 122; one or more set(s)of candidate power control parameters, estimated path loss informationand/or other small cell uplink power control information. In variousembodiments, transmitter 220 and receiver 222 can be connected to one ormore antenna(s) 224 to facilitate the transmission and/or reception ofcellular data and/or information to/from one or more UE (e.g., UE 112a-112 b) served by small cell radio 114 a using one or more over-the-aircontrol channels, data channels, combinations thereof or the like.

Referring to FIG. 2C, UE 112 a can include a transmitter 250, a receiver252, one or more antenna(s) 254, a user equipment storage 256, at leastone processor 262 and at least one memory element 264. In at least oneembodiment, at least one processor 262 is at least one hardwareprocessor configured to execute various tasks, operations and/orfunctions of UE 112 a as described herein and at least one memoryelement 264 is configured to store data associated with UE 112 a. Invarious embodiments, user equipment storage 256 can be configured tostore information associated with UE 112 a for the operation of UE 112a. In various embodiments, transmitter 250 and receiver 252 can beconnected to one or more antenna(s) 254 to facilitate the transmissionand/or reception of cellular data and/or information to/from one or morecell radios (e.g., small cell radio 114 a) using one or moreover-the-air control channels, data channels, combinations thereof orthe like.

In regards to the internal structure associated with communicationsystem 100, each of UE 112 b-112 d, small cell radio 114 b and macrocell radio 116 may each also include a respective processo, a respectivememory element and/or respective storage. Small cell radio 114 b canadditionally include one or more transmitters, receivers and/or antennasto facilitate over-the-air communications, a respective power managementmodule and respective storage. Hence, appropriate software, hardwareand/or algorithms are being provisioned in UE 112 a-112 d, small cellradio 114 a-114 b, macro cell radio 116 and central management system122 in order to facilitate small cell uplink power control and/orresource management operations as described for various embodimentsdiscussed herein. Note that in certain examples, certain databases(e.g., for storing information associated with uplink power controland/or resource management for communication system 100) can beconsolidated with memory elements (or vice versa), or the storage canoverlap/exist in any other suitable manner.

In one example implementation, UE 112 a-112 d, small cell radio 114a-114 b, macro cell radio 116 and central management system 122 arenetwork elements, which are meant to encompass network appliances,servers, routers, switches, gateways, bridges, loadbalancers, firewalls,processors, modules, or any other suitable device, component, element,or object operable to exchange information that facilitates or otherwisehelps coordinate small cell uplink power control and/or resourcemanagement operations (e.g., for networks such as those illustrated inFIG. 1A). In other embodiments, these operations and/or features may beprovided external to these elements, or included in some other networkdevice to achieve this intended functionality. Alternatively, one ormore of these elements can include software (or reciprocating software)that can coordinate in order to achieve the operations and/or features,as outlined herein. In still other embodiments, one or more of thesedevices may include any suitable algorithms, hardware, software,components, modules, interfaces, or objects that facilitate theoperations thereof. This may be inclusive of appropriate algorithms andcommunication protocols that allow for the effective exchange of data orinformation.

In various embodiments, UE 112 a-112 d, small cell radio 114 a-114 b,macro cell radio 116 and central management system 122 may keepinformation in any suitable memory element [e.g., random access memory(RAM), read only memory (ROM), an erasable programmable read only memory(EPROM), application specific integrated circuit (ASIC), etc.],software, hardware, or in any other suitable component, device, element,or object where appropriate and based on particular needs. Any of thememory items discussed herein should be construed as being encompassedwithin the broad term ‘memory element’. Information being tracked orsent to UE 112 a-112 d, small cell radio 114 a-114 b, macro cell radio116 and central management system 122 could be provided in any database,register, control list, cache, or storage structure: all of which can bereferenced at any suitable timeframe. Any such storage options may beincluded within the broad term ‘memory element’ as used herein.Similarly, any of the potential processing elements, modules, andmachines described herein should be construed as being encompassedwithin the broad term ‘processor’. Each of the network elements and/oruser equipment can also include suitable interfaces for receiving,transmitting, and/or otherwise communicating data or information in anetwork environment.

Note that in certain example implementations, the small cell uplinkpower control and/or resource management functions as outlined hereinmay be implemented by logic encoded in one or more tangible media, whichmay be inclusive of non-transitory media (e.g., embedded logic providedin an ASIC, in digital signal processing (DSP) instructions, software[potentially inclusive of object code and source code] to be executed bya processor, or other similar machine, etc.). In some of theseinstances, memory elements [as shown in FIGS. 2A-2C] can store data usedfor the operations described herein. This includes the memory elementsbeing able to store software, logic, code, or processor instructionsthat are executed to carry out the activities described herein. Aprocessor (e.g., a hardware processor) can execute any type ofinstructions associated with the data to achieve the operations detailedherein. In one example, the processors [as shown in FIGS. 2A-2C] couldtransform an element or an article (e.g., data, information) from onestate or thing to another state or thing. In another example, theactivities outlined herein may be implemented with fixed logic orprogrammable logic (e.g., software/computer instructions executed by aprocessor) and the elements identified herein could be some type of aprogrammable processor, programmable digital logic (e.g., a fieldprogrammable gate array (FPGA), a DSP processor, an EPROM, anelectrically erasable PROM (EEPROM) or an ASIC that includes digitallogic, software, code, electronic instructions, or any suitablecombination thereof.

Turning to FIG. 3, FIG. 3 is a simplified flow diagram illustratingexample operations 300 associated with providing small cell uplink powercontrol in a network environment in accordance with one potentialembodiment of communication system 100. In particular, operations 300can be associated with the first operational architecture in which oneor more small cell radios of a plurality of small cell radios (e.g.,small cell radios 114 a-114 b) may determine one or more set(s) ofcandidate power control parameters using the first interferenceconstraint. In various embodiments, the operations can be performed viaone or more of small cell radios 114 a-114 b and a central managemententity (e.g., central management system 122).

At any time, uplink transmissions can be scheduled for user equipmentconnected among one or more neighboring small cell radios (e.g., UE 112a-112 b associated with small cell radio 114 a, UE 112 c associated withsmall cell radio 112 b) for a small cell deployment of communicationsystem 100. Accordingly, the operations can begin at 302 in which one ormore small cell radio(s) (e.g., small cell radio 114 a, 114 b) maycalculate one or more set(s) of power control parameters (e.g., P₀ andα) using a first interference constraint for uplink UE transmissions forUE served by the one or more small cell radio(s). In variousembodiments, the first interference constraint can be associated with asystem of equations (e.g., Equation System 1 based on Equation 1)associated, at least in part, with interference generated towards eachof the small cell radio(s) by one or more UE associated with at leastone macro cell radio (e.g., UE 112 d associated with macro cell radio116) in a vicinity (e.g., having an overlapping coverage area) of thesmall cell radio(s).

In some embodiments, depending on configuration (e.g., operator, serviceprovider, etc. configuration), a central management entity (e.g.,central management system 122) can be configured to task each of theplurality of small cell radios in a small cell deployment to calculateone or more set(s) of candidate power control parameters according tothe first interference constraint. In other embodiments, depending onconfiguration, the central management entity can be configured to task aparticular small cell radio that may be determined to experience thehighest interference from UEs associated with a dominant macro cellradio to calculate one or more set(s) of candidate set(s) of powercontrol parameters according to the first interference constraint.

At 304, the operations can include receiving, at a central managemententity (e.g., central management system 122), the one or more set(s) ofcandidate of power control parameters generated by the one or more smallcell radio(s). At 306, the operations can include determining, at thecentral management entity, whether an average of a sum of an expectedinterference for UE associated with the plurality of small cell radiosviolates a second interference constraint for any of the one or moreset(s) of candidate power control parameters. In various embodiments,the second interference constraint can be associated with interferencethat may be generated by small cell UE associated with the plurality ofsmall cell radios towards the at least one macro cell radio (e.g., asrepresented by Equation 2). In various embodiments, the determiningperformed by the central management entity can include determiningwhether the average of the sum expected interference that may be causedby the UE according to a given set of candidate power control parametersfor each of the plurality of small cell radios exceeds a maximumallowable interference that can be caused towards the at least one macrocell.

At 308, the operations can include generating a message for each of theplurality of small cell radios identifying one or more set(s) ofparticular (e.g., optimized) power control parameters that provide forsatisfying the second interference constraint and the operations mayend. In some embodiments, the operations can include, at 310, each smallcell radio setting relative uplink power levels for small cell UEassociated thereto according to an ICIC framework that seeks to reduceinterference between neighboring small cell radios. Accordingly, asshown in operations 300, communication system 100 may provide for amethod to facilitate small cell uplink power control in a networkenvironment in accordance with one embodiment of the present disclosure.

Turning to FIG. 4, FIG. 4 is a simplified flow diagram illustratingother example operations 400 associated with providing small cell uplinkpower control in a network environment in accordance with one potentialembodiment of communication system 100. In particular, exampleoperations 400 may be associated with a variation of the firstoperational architecture in which one or more small cell radio(s) and acentral management entity (e.g., central management system 122) mayoperate through iterative exchanges to determine a set of optimizedpower control parameters that meet the first and second interferenceconstraints. In various embodiments, the operations can be performed viaone or more of a plurality of small cell radios (e.g., cell radios small114 a-114 b) and a central management entity (e.g., central managementsystem 122).

At any time, uplink transmissions can be scheduled for user equipmentconnected among one or more neighboring small cell radios (e.g., UE 112a-112 b associated with small cell radio 114 a, UE 112 c associated withsmall cell radio 112 b) of communication system 100. Accordingly, theoperations can begin at 402 in which one or more small cell radio(s)(e.g., small cell radio(s) 114 a, 114 b) may set a minimum cell edgeSINR threshold value for cell edge UE uplink transmissions (e.g., 5 dB)and a minimum cell interior SINR threshold value for cell interior UEuplink transmissions (e.g., 15 dB). In some embodiments, centralmanagement system 122 may communicate a minimum cell edge UE SINRthreshold value and a minimum cell interior SINR threshold value for oneor more small cell radio(s).

At 404, the operations can include the one or more small cell radio(s)calculating a set of candidate power control parameters (e.g., P₀ and α)using a first interference constraint for uplink UE transmissions for UEserved by the one or more small cell radio(s). In various embodiments,the first interference constraint can be associated with a system ofequations based on Equation 1 in which the minimum cell edge SINRthreshold value and the minimum cell interior SINR threshold value canbe used to determine the set of candidate power control parameters. At406, the operations can include communicating the respective set ofcandidate power control parameters as calculated by each of the one ormore respective small cell radio(s) to a central management entity(e.g., central management system 122).

In some embodiments, depending on configuration (e.g., operator, serviceprovider, etc. configuration), the central management entity can beconfigured to task each small cell radio 144 a and 144 b to performoperations 402, 404 and 406. In other embodiments, depending onconfiguration, the central management entity can be configured todetermine a particular small cell radio that is experiencing the highestinterference from macro cell UE and may select that particular smallcell radio to perform operations 402, 404 and 406. In variousembodiments, a determination of which of one or more small cell radiosmay be experiencing a highest macro cell UE interference can beperformed by the central management entity using values of I_(MACRO)(c)for each small cell radio, which can be calculated by the centralmanagement entity or can calculated by each small cell radio andreported to the central management entity.

At 408, the central management entity determines whether an average of asum of an expected interference for small cell UE associated with theplurality of small cell radios violates a second interference constraintassociated with a maximum interference that may be caused by small cellUE associated with the small cell radios towards at least one macro cellradio (e.g., a dominant macro cell radio such as, for example, macrocell radio 116) for respective sets of candidate power controlparameters received from the one or more respective small cell radios.

If at 408, the central management entity determines that the secondinterference constraint is not satisfied, the operations can continue to410 in which the central management entity can request the one or moresmall cell radio(s) to calculate a new set of candidate power controlparameters. At 412, each of the one or more small cell radio(s) maydetermine whether the current cell interior SINR value is greater thanthe current cell edge SINR value. If a given cell radio determines thatthe current cell interior SINR value is greater than the current SINRvalue used for its first interference constraint calculations,operations for the given small cell radio can continue to 414 in whichthe cell interior SINR value can be reduced by a predetermined amountand the operations can return to 404 for the given small cell radio inwhich a new set of candidate power control parameters can be calculatedaccording to the first interference constraint using the reduced cellinterior SINR value. In various embodiments, the predetermined amountcan be a predetermined step size, which can be varied in size fromapproximately 0.5 dB to approximately 1 dB.

However, If a given cell radio determines that its current cell interiorSINR value is not greater than the current SINR value used for its firstinterference constraint calculations (e.g., if they are equal to eachother), operations for the given small cell radio can continue to 416 inwhich both the cell interior SINR value and the cell edge SINR value canbe reduced by a predetermined amount and the operations can return to404 for the given small cell radio in which a new set of candidate powercontrol parameters can be calculated according the first interferenceconstraint using the reduced cell interior SINR value and the reducedcell edge SINR value.

The operations at 404, 406, 408, 410, 412 and 414 or 416 can continueuntil the central management entity determines that the secondinterference constraint is satisfied (e.g., the maximum expectedinterference to be caused towards macro cell radio 116 is below amaximum interference threshold) in which case the operations cancontinue to 418. At 418, the central management entity may generate oneor more message(s) to each small cell radio identifying one or moreset(s) of optimized power control parameters that provide for satisfyingthe second interference constraint and the operations may end. In someembodiments, each small cell radio 114 a-114 b may receive the sameset(s) of optimized power control parameters (e.g., if one small cellradio is tasked with calculating set(s) of candidate power controlparameters for a group or cluster of small cell radios). In otherembodiments, each small cell radio 114 a-114 b may receive cell-specificset(s) of optimized power control parameters (e.g., if each small cellradio in a group or cluster is tasked with calculating set(s) ofcandidate power control parameters). In some embodiments, the operationscan include, at 420, each small cell radio setting relative uplink powerlevels for small cell UE associated thereto according to an ICICframework that seeks to reduce interference between neighboring smallcell radios.

Turning to FIG. 5, FIG. 5 is a simplified flow diagram illustrating yetother example operations 500 associated with providing small cell uplinkpower control in a network environment in accordance with one potentialembodiment of communication system 100. In particular, exampleoperations 500 may be associated with another variation of the firstoperational architecture in which one or more small cell radio(s) maycalculate multiple sets of candidate power control parameters that meetto first interference constraint to feed to a central management entity(e.g., central management system 122), which may search the sets todetermine one or more set(s) of optimized power control parameters thatmeet second interference constraint. In various embodiments, theoperations can be performed via one or more of a plurality of small cellradios (e.g., cell radios small 114 a-114 b) and a central managemententity (e.g., central management system 122).

At any time, uplink transmissions can be scheduled for user equipmentconnected among one or more neighboring small cell radios (e.g., UE 112a-112 b associated with small cell radio 114 a, UE 112 c associated withsmall cell radio 112 b) of communication system 100. Accordingly, theoperations can begin at 502 in which one or more small cell radio(s)(e.g., small cell radio(s) 114 a, 114 b) may calculate multiple sets ofcandidate power control parameters using a first interference constraintfor uplink UE transmissions for small cell UE served by the one or moresmall cell radio(s). In various embodiments, the first interferenceconstraint can be associated with a system of equations based onEquation 1 in which a first range of cell edge SINR threshold values anda second range of cell interior SINR threshold values can be used todetermine the multiple sets of candidate power control parameters.

At 504, the operations can include communicating the respective sets ofcandidate power control parameters as calculated by the one or morerespective small cell radio(s) to a central management entity (e.g.,central management system 122). In some embodiments, depending onconfiguration (e.g., operator, service provider, etc. configuration),the central management entity can be configured to task each small cellradio 144 a and 144 b to perform operations 502 and 504. In otherembodiments, depending configuration, the central management entity canbe configured to determine a particular small cell radio that isexperiencing the highest interference from macro cell UE and may selectthat particular small cell radio to perform operations 502 and 504. Invarious embodiments, a determination of which of one or more small cellradios may be experiencing a highest macro cell UE interference can beperformed by the central management entity using values of I_(MACRO)(c)for each small cell radio, which can be calculated by the centralmanagement entity or can calculated by each small cell radio andreported to the central management entity.

At 506, the central management entity can search the respective sets ofcandidate power control parameters to determine one or more set(s) ofoptimized power control parameters that meet a second interferenceconstraint associated with a maximum interference that may be caused bysmall cell UE associated with the small cell radios towards at least onemacro cell radio (e.g., a dominant macro cell radio such as, forexample, macro cell radio 116). At 508, the central management entitymay generate one or more message(s) to each small cell radio identifyingone or more set(s) of optimized power control parameters that providefor meeting the second interference constraint and the operations mayend. In some embodiments, each small cell radio 114 a-114 b may receivethe same set(s) of optimized power control parameters (e.g., if onesmall cell radio is tasked with calculating set(s) of candidate powercontrol parameters for a group or cluster of small cell radios). Inother embodiments, each small cell radio 114 a-114 b may receivecell-specific set(s) of optimized power control parameters (e.g., ifeach small cell radio in a group or cluster is tasked with calculatingset(s) of candidate power control parameters).

In some embodiments, the operations can include, at 510, each small cellradio setting relative uplink power levels for small cell UE associatedthereto according to an ICIC framework that seeks to reduce interferencebetween neighboring small cell radios. In various embodiments,operations 500 as shown in FIG. 5 may provide for reduced signalingbetween central management system 122 and one or more small cellradio(s) 114 a, 114 b as compared to operations 400 as shown in FIG. 4in order to facilitate providing small cell uplink power control forcommunication system 100.

Turning to FIG. 6, FIG. 6 is a simplified flow diagram illustratingexample operations 600 associated with providing small cell uplink powercontrol in a network environment in accordance with one potentialembodiment of communication system 100. In particular, operations 600can be associated with the second operational architecture in which acentral management entity (e.g., central management system 122) candetermine one or more set(s) of optimized power control parameters basedon estimated path loss information received from one or more small cellradios of a plurality of small cell radios (e.g., small cell radios 114a-114 b). In various embodiments, the operations can be performed viaone or more of small cell radios 114 a-114 b and a central managemententity (e.g., central management system 122).

At any time, uplink transmissions can be scheduled for user equipmentconnected among one or more neighboring small cell radios (e.g., UE 112a-112 b associated with small cell radio 114 a, UE 112 c associated withsmall cell radio 112 b) for a small cell deployment of communicationsystem 100. Accordingly, the operations can begin at 602 in which UEpath loss information associated with one or more UE served by one ormore small cell radio(s) 114 a, 114 b can be determined. At 604, macropath loss information associated with each of the one or more small cellradio(s) 114 a, 114 b and a dominant macro cell radio (e.g., macro cellradio 116) can be determined.

At 606, the operations can include determining, at a central managemententity (e.g., central management system 122, via central powermanagement module 150), one or more set(s) of optimized power controlparameters for uplink UE transmissions for the one or more UE served bythe one or more small cell radios. In various embodiments, the one ormore set(s) of optimized power control parameters may satisfy the firstinterference constraint associated with limiting interference betweenthe one or more small cell radios for UE transmissions that may overcomeinterference caused by one or more macro UE served by the dominant macrocell radio and the one or more set(s) of optimized power controlparameters may satisfy the second interference constraint associatedwith limiting interference toward the dominant macro cell radio.

At 608, the central management entity may generate one or moremessage(s) to each small cell radio identifying one or more set(s) ofoptimized power control parameters that provide for meeting the secondinterference constraint and the operations may end. In some embodiments,each small cell radio 114 a-114 b may receive the same set(s) ofoptimized power control parameters (e.g., if one small cell radio istasked with calculating set(s) of candidate power control parameters fora group or cluster of small cell radios). In other embodiments, eachsmall cell radio 114 a-114 b may receive cell-specific set(s) ofoptimized power control parameters (e.g., if each small cell radio in agroup or cluster is tasked with calculating set(s) of candidate powercontrol parameters).

In some embodiments, the operations can include, at 610, each small cellradio setting relative uplink power levels for small cell UE associatedthereto according to an ICIC framework that seeks to reduce interferencebetween neighboring small cell radios.

Turning to FIG. 7, FIG. 7 is a simplified flow diagram illustratingexample operations 700 associated with providing small cell uplink powercontrol in a network environment in accordance with one potentialembodiment of communication system 100. In particular, operations 700can be associated with the second operational architecture in which acentral management entity (e.g., central management system 122) candetermine one or more set(s) of optimized power control parameters basedon estimated path loss information received from one or more small cellradios of a plurality of small cell radios (e.g., small cell radios 114a-114 b). In various embodiments, the operations can be performed viaone or more of small cell radios 114 a-114 b and a central managemententity (e.g., central management system 122).

At 702, the operations can include receiving, at a central managemententity, UE path loss information associated with one or more UE servedby one or more small cell radio(s) 114 a-114 b and macro path lossinformation associated with each of the one or more small cell radio(s)and a dominant macro cell radio. At 704, the central management entitycan calculate one or more set(s) of candidate power control parametersfor a first interference constraint associated with limitinginterference between the one or more small cell radios for UEtransmissions that may overcome interference caused by one or more macroUE served by the dominant macro cell radio.

At 706, the central management entity can determine whether an averageof a sum of an expected interference for the one or more UE served bythe one or more small cell radio(s) satisfies a second interferenceconstraint for any of the one or more set(s) of candidate power controlparameters. In various embodiments, the second interference constraintcan be associated with interference that may be generated by small cellUE towards the at least one macro cell radio (e.g., as represented byEquation 2). In various embodiments, the determining performed by thecentral management entity can include determining whether the average ofthe sum expected interference that may be caused by the UE according toa given set of candidate power control parameters for each of theplurality of small cell radios exceeds a maximum allowable interferencethat can be caused towards the at least one macro cell radio.

At 708, the central management entity can identify one or more set(s) ofoptimized power control parameters, which correspond to any of the oneor more set(s) of candidate power control parameters that satisfy thesecond interference constraint. At 710, the central management entitymay generate one or more message(s) to each small cell radio identifyingone or more set(s) of optimized power control parameters that providefor meeting the second interference constraint and the operations mayend. In some embodiments, each small cell radio 114 a-114 b may receivethe same set(s) of optimized power control parameters (e.g., if onesmall cell radio is tasked with calculating set(s) of candidate powercontrol parameters for a group or cluster of small cell radios). Inother embodiments, each small cell radio 114 a-114 b may receivecell-specific set(s) of optimized power control parameters (e.g., ifeach small cell radio in a group or cluster is tasked with calculatingset(s) of candidate power control parameters).

In some embodiments, the operations can include, at 712, each small cellradio setting relative uplink power levels for small cell UE associatedthereto according to an ICIC framework that seeks to reduce interferencebetween neighboring small cell radios.

Note that in this Specification, references to various features (e.g.,elements, structures, modules, components, steps, operations,characteristics, etc.) included in one embodiment′, ‘exampleembodiment’, an embodiment′, ‘another embodiment’, ‘certainembodiments’, some embodiments′, ‘various embodiments’, ‘otherembodiments’, ‘alternative embodiment’, and the like are intended tomean that any such features are included in one or more embodiments ofthe present disclosure, but may or may not necessarily be combined inthe same embodiments. Note also that a module as used herein thisSpecification, can be inclusive of an executable file comprisinginstructions that can be understood and processed on a computer, and mayfurther include library modules loaded during execution, object files,system files, hardware logic, software logic, or any other executablemodules.

It is also important to note that the operations and steps describedwith reference to the preceding FIGURES illustrate only some of thepossible scenarios that may be executed by, or within, the system. Someof these operations may be deleted or removed where appropriate, orthese steps may be modified or changed considerably without departingfrom the scope of the discussed concepts. In addition, the timing ofthese operations may be altered considerably and still achieve theresults taught in this disclosure. The preceding operational flows havebeen offered for purposes of example and discussion. Substantialflexibility is provided by the system in that any suitable arrangements,chronologies, configurations, and timing mechanisms may be providedwithout departing from the teachings of the discussed concepts.

Note that with the examples provided above, as well as numerous otherexamples provided herein, interaction may be described in terms of one,two, three, or four network elements. However, this has been done forpurposes of clarity and example only. In certain cases, it may be easierto describe one or more of the functionalities by only referencing alimited number of network elements. It should be appreciated thatcommunication system 100 (and its teachings) are readily scalable andcan accommodate a large number of components, as well as morecomplicated/sophisticated arrangements and configurations. Accordingly,the examples provided should not limit the scope or inhibit the broadteachings of communication system 100 as potentially applied to a myriadof other architectures.

Although the present disclosure has been described in detail withreference to particular arrangements and configurations, these exampleconfigurations and arrangements may be changed significantly withoutdeparting from the scope of the present disclosure. For example,although the present disclosure has been described with reference toparticular communication exchanges involving certain network access andprotocols, communication system 100 may be applicable to other exchangesor routing protocols. Moreover, although communication system 100 hasbeen illustrated with reference to particular elements and operationsthat facilitate the communication process, these elements, andoperations may be replaced by any suitable architecture or process thatachieves the intended functionality of communication system 100.

Numerous other changes, substitutions, variations, alterations, andmodifications may be ascertained to one skilled in the art and it isintended that the present disclosure encompass all such changes,substitutions, variations, alterations, and modifications as fallingwithin the scope of the appended claims. In order to assist the UnitedStates Patent and Trademark Office (USPTO) and, additionally, anyreaders of any patent issued on this application in interpreting theclaims appended hereto, Applicant wishes to note that the Applicant: (a)does not intend any of the appended claims to invoke paragraph six (6)of 35 U.S.C. section 112 as it exists on the date of the filing hereofunless the words “means for” or “step for” are specifically used in theparticular claims; and (b) does not intend, by any statement in thespecification, to limit this disclosure in any way that is not otherwisereflected in the appended claims.

1. A method comprising: calculating, by one or more of a plurality ofsmall cell radios, one or more sets of candidate power controlparameters using a first interference constraint for uplink userequipment (UE) transmissions for UE served by the one or more of theplurality of small cell radios; receiving, at a central managemententity, the one or more sets of candidate power control parameters fromeach of the one or more of the plurality of small cell radios;determining, at the central management entity, whether an average of asum of an expected interference for UE associated with the plurality ofsmall cell radios violates a second interference constraint for any ofthe one or more sets of candidate power control parameters; generatingone or more messages for each of the plurality of small cell radiosidentifying one or more particular sets of power control parameters thatprovide for meeting the second interference constraint; and setting, byeach small cell radio of the plurality of small cell radios, uplinktransmit power for each UE served by each small cell radio based, atleast in part, on the identified one or more particular sets of powercontrol parameters.
 2. The method of claim 1, wherein each set of powercontrol parameters includes: a first power control parameter associatedwith a power offset for UE transmissions toward a particular small cellradio; and a second power control parameter associated with an amount ofpath loss between UE and the particular small cell radio that isinverted for UE transmissions toward the particular small cell radio. 3.The method of claim 1, wherein the first interference constraint isassociated, at least in part, with interference generated towards eachof the one or more of the plurality of small cell radios by one or moreUE associated with at least one macro cell radio.
 4. The method of claim1, wherein the second interference constraint is associated, at least inpart, with interference generated by the UE associated with theplurality of small cell radios towards at least one macro cell radio. 5.The method of claim 1, wherein for a particular small cell radiocalculating a particular set of candidate power control parametersfurther comprises: setting a first expected Signal to Interference plusNoise Ratio (SINR) threshold value associated with cell edge UE servedby the particular small cell radio for the first interferenceconstraint; setting a second expected SINR threshold value associatedwith cell interior UE served by the particular small cell radio for thefirst interference constraint; calculating the particular set ofcandidate power control parameters for the particular small cell radiousing the first expected SINR threshold value and the second expectedSINR threshold value for the first interference constraint; andgenerating a message toward the central management entity including theparticular set of candidate power control parameters.
 6. The method ofclaim 5, further comprising: reducing at least one of the secondexpected SINR threshold value associated with cell interior UE or thefirst expected SINR threshold value associated with cell edge UE if thecentral management entity determines that the second interferenceconstraint is violated; and repeating the calculating and the generatingfor the particular small cell radio until the central management entitydetermines that the second interference constraint is satisfied.
 7. Themethod of claim 1, wherein for a particular small cell radio calculatingsets of candidate power control parameters further comprises: setting afirst range of first expected Signal to Interference plus Noise Ratio(SINR) threshold values associated with cell edge UE served by theparticular small cell radio for the first interference constraint;setting a second range of second expected SINR threshold valuesassociated with cell interior UE served by the particular small cellradio for the first interference constraint; calculating sets ofcandidate power control parameters for the particular small cell radiousing each of the first expected SINR threshold value of the first rangeand each of the second expected SINR threshold value of the second rangefor the first interference constraint; and generating one or moremessages toward the central management entity including the sets ofcandidate power control parameters.
 8. The method of claim 1, whereinthe central management entity is a Self-Organizing Network (SON)management system in communication with each of the plurality of smallcell radios.
 9. One or more non-transitory tangible media encoding logicthat includes instructions for execution that when executed by aprocessor, is operable to perform operations comprising: calculating, byone or more of a plurality of small cell radios, one or more sets ofcandidate power control parameters using a first interference constraintfor uplink user equipment (UE) transmissions for UE served by the one ormore of the plurality of small cell radios; receiving, at a centralmanagement entity, the one or more sets of candidate power controlparameters from each of the one or more of the plurality of small cellradios; determining, at the central management entity, whether anaverage of a sum of an expected interference for UE associated with theplurality of small cell radios violates a second interference constraintfor any of the one or more sets of candidate power control parameters;generating one or more messages for each of the plurality of small cellradios identifying one or more particular sets of power controlparameters that provide for meeting the second interference constraint;and setting, by each small cell radio of the plurality of small cellradios, uplink transmit power for each UE served by each small cellradio based, at least in part, on the identified one or more particularsets of power control parameters.
 10. The media of claim 9, wherein eachset of power control parameters includes: a first power controlparameter associated with a power offset for UE transmissions toward aparticular small cell radio; and a second power control parameterassociated with an amount of path loss between UE and the particularsmall cell radio that is inverted for UE transmissions toward theparticular small cell radio.
 11. The media of claim 9, wherein the firstinterference constraint is associated, at least in part, withinterference generated towards each of the one or more of the pluralityof small cell radios by one or more UE associated with at least onemacro cell radio.
 12. The media of claim 9, wherein the secondinterference constraint is associated, at least in part, withinterference generated by the UE associated with the plurality of smallcell radios towards at least one macro cell radio.
 13. The media ofclaim 9, wherein for a particular small cell radio calculating aparticular set of candidate power control parameters further comprises:setting a first expected Signal to Interference plus Noise Ratio (SINR)threshold value associated with cell edge UE served by the particularsmall cell radio for the first interference constraint; setting a secondexpected SINR threshold value associated with cell interior UE served bythe particular small cell radio for the first interference constraint;calculating the particular set of candidate power control parameters forthe particular small cell radio using the first expected SINR thresholdvalue and the second expected SINR threshold value for the firstinterference constraint; and generating a message toward the centralmanagement entity including the particular set of candidate powercontrol parameters.
 14. The media of claim 13, the operations furthercomprising: reducing at least one of the second expected SINR thresholdvalue associated with cell interior UE or the first expected SINRthreshold value associated with cell edge UE if the central managemententity determines that the second interference constraint is violated;and repeating the calculating and the generating for the particularsmall cell radio until the central management entity determines that thesecond interference constraint is satisfied.
 15. The media of claim 9,wherein for a particular small cell radio calculating sets of candidatepower control parameters further comprises: setting a first range offirst expected Signal to Interference plus Noise Ratio (SINR) thresholdvalues associated with cell edge UE served by the particular small cellradio for the first interference constraint; setting a second range ofsecond expected SINR threshold values associated with cell interior UEserved by the particular small cell radio for the first interferenceconstraint; calculating sets of candidate power control parameters forthe particular small cell radio using each of the first expected SINRthreshold value of the first range and each of the second expected SINRthreshold value of the second range for the first interferenceconstraint; and generating one or more messages toward the centralmanagement entity including the sets of candidate power controlparameters.
 16. A system, comprising: at least one memory element forstoring data; and at least one processor that executes instructionsassociated with the data, wherein the at least one processor and the atleast one memory element cooperate such that the system is configuredfor: calculating, by one or more of a plurality of small cell radios,one or more sets of candidate power control parameters using a firstinterference constraint for uplink user equipment (UE) transmissions forUE served by the one or more of the plurality of small cell radios;receiving, at a central management entity, the one or more sets ofcandidate power control parameters from each of the one or more of theplurality of small cell radios; determining, at the central managemententity, whether an average of a sum of an expected interference for UEassociated with the plurality of small cell radios violates a secondinterference constraint for any of the one or more sets of candidatepower control parameters; generating one or more messages for each ofthe plurality of small cell radios identifying one or more particularsets of power control parameters that provide for meeting the secondinterference constraint; and setting, by each small cell radio of theplurality of small cell radios, uplink transmit power for each UE servedby each small cell radio based, at least in part, on the identified oneor more particular sets of power control parameters.
 17. The system ofclaim 16, wherein the first interference constraint is associated, atleast in part, with interference generated towards each of the one ormore of the plurality of small cell radios by one or more UE associatedwith at least one macro cell radio and wherein the second interferenceconstraint is associated, at least in part, with interference generatedby the UE associated with the plurality of small cell radios towards theat least one macro cell radio.
 18. The system of claim 16, wherein for aparticular small cell radio calculating a particular set of candidatepower control parameters further comprises: setting a first expectedSignal to Interference plus Noise Ratio (SINR) threshold valueassociated with cell edge UE served by the particular small cell radiofor the first interference constraint; setting a second expected SINRthreshold value associated with cell interior UE served by theparticular small cell radio for the first interference constraint;calculating the particular set of candidate power control parameters forthe particular small cell radio using the first expected SINR thresholdvalue and the second expected SINR threshold value for the firstinterference constraint; and generating a message toward the centralmanagement entity including the particular set of candidate powercontrol parameters.
 19. The system of claim 18, wherein the system isfurther configured for: reducing at least one of the second expectedSINR threshold value associated with cell interior UE or the firstexpected SINR threshold value associated with cell edge UE if thecentral management entity determines that the second interferenceconstraint is violated; and repeating the calculating and the generatingfor the particular small cell radio until the central management entitydetermines that the second interference constraint is satisfied.
 20. Thesystem of claim 16, wherein for a particular small cell radiocalculating sets of candidate power control parameters furthercomprises: setting a first range of first expected Signal toInterference plus Noise Ratio (SINR) threshold values associated withcell edge UE served by the particular small cell radio for the firstinterference constraint; setting a second range of second expected SINRthreshold values associated with cell interior UE served by theparticular small cell radio for the first interference constraint;calculating sets of candidate power control parameters for theparticular small cell radio using each of the first expected SINRthreshold value of the first range and each of the second expected SINRthreshold value of the second range for the first interferenceconstraint; and generating one or more messages toward the centralmanagement entity including the sets of candidate power controlparameters.